Are you getting lots of pop-ups? Have you
seen other weird problems crop up? If so,
your PC might be infected with a virus,
spyware, or other malware—even if you have
an antivirus program installed. Though other
problems such as hardware issues can
produce similarly annoying symptoms, it’s
best to check for malware if your PC is
acting up and we’ll show you how to do it
yourself.
Step 1: Enter Safe Mode
Before you do anything, you need to
disconnect your PC from the internet, and
don’t use it until you’re ready to clean your
PC. This can help prevent the malware from
spreading and/or leaking your private data.
If you think your PC may have a malware
infection, boot your PC into Microsoft’s Safe
Mode . In this mode, only the minimum
required programs and services are loaded.
If any malware is set to load automatically
when Windows starts, entering in this mode
may prevent it from doing so. This is
important because it allows the files to be
removed easier since they’re not actually
running or active.
Sadly, Microsoft has turned the process of
booting into safe mode from a relatively
easy process in Windows 7 and Windows 8
to one that is decidedly more complicated in
Windows 10. To boot into Windows Safe
Mode, first click the Start Button in Windows
10 and select the Power button as if you
were going to reboot, but don’t click
anything. Next hold down the Shift key and
click Reboot. When the full-screen menu
appears, select Troubleshooting , then
Advanced Options, then Startup Settings . On
the next window click the Restart button and
wait for the next screen to appear (just stick
with us here, we know this is long). Next you
will see a menu with numbered startup
options; select number 4, which is Safe
Mode. Note that if you want to connect to
any online scanners you’ll need to select
option 5, which is Safe Mode with
Networking.
You may find that your PC runs noticeably
faster in Safe Mode. This could be a sign
that your system has a malware infection, or
it could mean that you have a lot of
legitimate programs that normally start up
alongside Windows. If your PC is outfitted
with a solid state drive it’s probably fast
either way.
Step 2: Delete temporary files
You can use Windows 10’s built-in disk cleanup
utility to rid your system of unnecessary temp
files.
Now that you’re in Safe Mode, you’ll
want to run a virus scan. But before you do
that, delete your temporary files. Doing this
may speed up the virus scanning, free up
disk space, and even get rid of some
malware. To use the Disk Cleanup utility
included with Windows 10 just type Disk
Cleanup in the search bar or after pressing
the Start button and select the tool that
appears named Disk Cleanup.
Step 3: Download malware
scanners
Now you’re ready to have a malware scanner
do its work—and fortunately, running a
scanner is enough to remove most standard
infections. If you already had an antivirus
program active on your computer, you should
use a different scanner for this malware
check, since your current antivirus software
may not have detected the malware.
Remember, no antivirus program can detect
100 percent of the millions of malware types
and variants.
There are two types of antivirus programs.
You’re probably more familiar with real-time
antivirus programs, which run in the
background and constantly watch for
malware. Another option is an on-demand
scanner, which searches for malware
infections when you open the program
manually and run a scan. You should have
only one real-time antivirus program installed
at a time, but you can have many on-demand
scanners installed to run scans with multiple
programs, thereby ensuring that if one
program misses something a different one
might find it.
If you think your PC is infected, we
recommend using an on-demand scanner
first and then following up with a full scan by
your real-time antivirus program. Among the
free (and high-quality) on-demand scanners
available are BitDefender Free Edition ,
Kaspersky Virus Removal Tool ,
Malwarebytes, Microsoft’s Malicious
Software Removal Tool , Avast, and
SuperAntiSpyware .
Step 4: Run a scan with
Malwarebytes
For illustrative purposes, we’ll describe how
to use the Malwarebytes on-demand
scanner. To get started, download it. If you
disconnected from the internet for safety
reasons when you first suspected that you
might be infected, reconnect to it so you can
download, install, and update Malwarebytes;
then disconnect from the internet again
before you start the actual scanning. If you
can’t access the internet or you can’t
download Malwarebytes on the infected
computer, download it on another computer,
save it to a USB flash drive, and take the
flash drive to the infected computer.
After downloading Malwarebytes, run the
setup file and follow the wizard to install the
program. Once the program opens, it will
automatically activate a trial of the paid
version that enables real-time scanning. You
won’t get charged after the trial ends,
however—by default, the program reverts to
the standard free version in 14 days. In the
meanwhile, you can disable the real-time
scanning for those two weeks if you prefer.
To run a scan, switch from the Dashboard
tab to the Scan tab. Keep the default scan
option (“Threat Scan”) selected and click the
Start Scan button. It should check for
updates before it runs the scan, but make
sure that happens before you proceed.
Choose Threat Scan to perform a basic
analysis of your computer’s most commonly
infected files.
Though it offers a custom-scan option,
Malwarebytes recommends that you perform
the threat scan first, as that scan usually
finds all of the infections anyway. Depending
on your computer, the quick scan can take
anywhere from 5 to 20 minutes, whereas a
custom scan might take 30 to 60 minutes or
more. While Malwarebytes is scanning, you
can see how many files or objects the
software has already scanned, and how
many of those files it has identified either as
being malware or as being infected by
malware.
If Malwarebytes automatically disappears
after it begins scanning and won’t reopen,
you probably have a rootkit or other deep
infection that automatically kills scanners to
prevent them from removing it. Though you
can try some tricks to get around this
malicious technique, you might be better off
reinstalling Windows after backing up your
files (as discussed later), in view of the time
and effort you may have to expend to beat
the malware.
Once the scan is complete, Malwarebytes
will show you the results. If the software
gives your system a clean bill of health but
you still think that your system has acquired
some malware, consider running a custom
scan with Malwarebytes and trying the other
scanners mentioned earlier. If Malwarebytes
does find infections, it’ll show you what they
are when the scan is complete. Click the
Remove Selected button in the lower left to
get rid of the specified
infections. Malwarebytes may also prompt
you to restart your PC in order to complete
the removal process, which you should do.
Malwarebytes presents the results of its
scan and lets you remove the offending bits
with one click.
If your problems persist after you’ve run the
threat scan and it has found and removed
unwanted files, consider running a full scan
with Malwarebytes and the other scanners
mentioned earlier. If the malware appears to
be gone, run a full scan with your real-time
antivirus program to confirm that result.
Step 5: Fix your web browser
Malware infections can damage Windows
system files and other settings. One
common malware trait is to modify your web
browser’s homepage to reinfect the PC,
display advertisements, prevent browsing,
and generally annoy you.
Before launching your web browser, check
your homepage and connection settings. For
Internet Explorer right-click the Windows 10
Start button and select Control Panel, then
Internet Options. Find the Home Page settings
in the General tab, and verify that it’s not
some site you know nothing about. For
Chrome, Firefox, or Edge, simply go to the
setttings window of your browser to check
your homepage setting.
Make sure that your homepage settings are
correct before launching Internet Explorer.
Step 6: Recover your files if
Windows is corrupt
If you can’t seem to remove the malware or
if Windows isn’t working properly, you may
have to reinstall Windows. But before wiping
your hard drive, copy all of your files to an
external USB or flash drive. If you check
your email with a client program (such as
Outlook or Windows Mail), make sure that
you export your settings and messages to
save them. You should also back up your
device drivers with a utility such as Double
Driver , in case you don’t have the driver
discs anymore or don’t want to download
them all again. Remember, you can’t save
installed programs. Instead, you’ll have to
reinstall the programs from discs or
redownload them.
If Windows won’t start or work well enough
to permit you to back up your files, you may
create and use a Live CD, such as Hiren’s
BootCD (HBCD) , to access your files.
Once you have backed up everything,
reinstall Windows either from the disc that
came with your PC, by downloading the
installation image from Microsoft, or by
using your PC’s factory restore option, if it
has one. For a factory restore you typically
must press a certain key on the keyboard
during the boot process in order for restore
procedure to initialize, and your PC should
tell you what key to press in the first few
seconds after you turn it on. It there’s no on-
screen instructions consult your manual, the
manufacturer, or Google.
Keeping your PC clean
Always make sure that you have a real-time
antivirus program running on your PC, and
make sure this program is always up-to-date.
If you don’t want to spend money on yearly
subscriptions, you can choose one of the
many free programs that provide adequate
protection, such as Avast, AVG, Panda,
or Comodo . You can read more about how to
find the best antivirus program for your
needs right here.
In addition to installing traditional antivirus
software, you might consider using the free
OpenDNS service to help block dangerous
sites. And if you frequent shady sites that
might infect your PC with malware, consider
running your web browser in sandbox mode
to prevent any downloaded malware from
harming your system. Some antivirus
programs, such as Comodo, offer sandboxing
features, or you can obtain them through a
free third-party program such as Sandboxie .
When you think that you’ve rid your PC of
malware infections, double-check your online
accounts, including those for your bank,
email, and social networking sites. Look for
suspicious activity and change your
passwords—because some malware can
capture your passwords.
If you have a backup system in place that
automatically backs up your files or system,
consider running virus scans on the backups
to confirm that they didn’t inadvertently
save infections. If virus scans aren’t
feasible, as is the case with online systems
since they usually will only scan a drive
attached to your PC or just the C:\ drive,
consider deleting your old backups and
resetting the software to begin saving new
backups that are hopefully free from
infections.
Keep Windows, other Microsoft software, and
Adobe products up-to-date. Make sure that
you have Windows Update turned on and
enabled to download and install updates
automatically. If you’re not comfortable with
this, set Windows to download the updates
but let you choose when to install them.
