Malware can infect your computer via many different ways; via junk email, malicious code from websites, downloaded files, and many more.
Sometimes the files sit, dormant, on your computer and will only activate at a later point in time.
There is no one program or solution to prevent infections like this, but by using a combination it is possible to reduce the risk significantly;
First and foremost, ensure you have active Virus and Malware protection. Check the software to see if it’s up to date – good software should be receiving “definition” updates often.
First try a copy of Malwarebytes Anti-Malware;
Click the link to download – https://www.malwarebytes.com/mwb-download/thankyou/
Right-click the downloaded file (at the time of writing mb3-setup-consumer-220.127.116.1111-1.0.527-1.0.8932.exe) and Run As Administrator.
Next, select Personal Computer, click Agree and Install, Finish.
Once installed run via the Shortcut, Click Get Started.
On the left menu, click Settings, Protection tab, ensure “Scan for Rootkits” is enabled
On the left menu, click Scan. Click Start Scan.
Once the scan is finished the software will alert you if there is anything nasty on your computer and give you the option to remove it.
Keep running the scan until you are told the PC is clean.
You can now remove the Malwarebytes software if you like.
Second – scan your pc with SuperAntiSpyware
Click the link to download – https://www.superantispyware.com/downloadfile.html?productid=SUPERANTISPYWAREFREE
Right-click the downloaded file (at the time of writing SUPERAntiSpyware.exe) and Run As Administrator.
Click Next, Agree, Remove the options to Include Google Chrome and make it your default Browser, Click Next, Next, Next, Next, Next, Finished.
Decline the trial.
Click “Scan this computer”
When scan is complete click Continue
On completed scan screen some items will be selected (red cross) and some will not. If the items that are not selected are either not known to you or look suspicious (if all else fails try a web search for the item) then select them.
Click Continue to clean the selected items from the computer
Some items will require a reboot to fully clean.
Again, repeat scan until nothing is reported.
NOTE: This process is not guaranteed to clean everything potentially malicious from your computer, but is a good start.