Not the fastet way, but the safest: format your drive and reinstall your OS.
The best thing to do is to have a good web behaviour:
Otherwise, once you "cleaned" your computer, you will catch/bring back malwares from your (or your friend's) USB flash drive or from an external hard drive, from a PDF document, from an infected website, from a link in a website or a mail....
Once your computer is clean: please apply these rules:
-1 never click anywhere, obviously on unknown message or box telling you "your computer is slow/infected/corrupted".
-2 never click on a url or a link embedded in an email, except for the confirmation email you just received from a log in.
-3 never open any attached doc in an email: download it, and scan it with your Antivirus. (see part 6)
-4 never use a kind of computer/booster software except CCleaner: piriform.com/ccleaner-5 use Mozilla Firefox, it is more secure than others, (note: if you used Chrome before, i suggest you to uninstall it as Chrome slows Firefox !!!), never record password with your browser.
-6 scan each downloads you make with your antivirus (except maybe windows update): dont scan the .zip or .rar file: extract them first AND scan the extracted folders.-7 always make your updates: Windows update, Firefox update, Adobe Flash & Acrobat update, but also Java and Silverlight's update.-8 full-scan your computer with Malwarebytes, under safe mode, each half-month, or if you feel your computer is very slow plug your USB flash drive and start a complete scan.
-open the start menu (the windows flag for windows 8 )
-type: msconfig.exe then press Enter.
-click the "Boot" Tab and choose "Safe boot", choose "Minimal" then click "ok" and " then "restart".
-Quarantine all the stuff you find except maybe your Cgminer, Sgminer, cudaminer software. if you find a Backdoor, a Trojan or a worm: Change all your password (use different passwords for each tools/forum/mail).
-After the scan, open the start menu (the windows flag for windows 8 ) and type: msconfig.exe then press Enter.
click the "Boot" Tab and uncheck Safe boot, then select "Make all boot settings permanent".
then click "ok", then "yes" (on the poped-up system configuration windows) and " then "restart".
-9 (optional but very useful) install Noscript (only for Firefox), in order to block Javascript, Flash or Silverlight, download: noscript.net/
tips for the settings: ghacks.net/2014/02/10/firefox-noscript-guide-waiting/
ghacks.net/2013/05/25/top-5-noscript-features-that-you-may-not-know-about/
you need to whitelist your trusted website, right click on the "S" of noscript (upper left corner of your browser) and left-click "allow exampleyourtrustedwebsite.com
tip: a middle click on the "S" of noscript Allow temporarily the website you visit.
-10 for Laptops: turn off the bluetooth connection: Click Menu Start ->Control Panel-> Network and Internet, then click "Network and Sharing Center" (on the left column of the Network and Sharing Center)
then click on "Change adapter settings" Right click "Bluetooth Network Connection", select "Disable".
If you apply these rules, on a clean computer:
it will be very safe !