Learn how to deal with problems like missing files, frequent crashes, a PC that won't boot, and more
You think your PC is infected
If your regular antivirus program -- the one you already have up and running -- hasn't stopped the questionable software, it probably can't. What you need is a second opinion, and possibly a third and a fourth.
Start with the free version of Malwarebytes Anti-Malware, a utility with an exceptional record of finding and removing malware. Download it, install it, launch it, update the database, and then perform a full scan.
Since installing and updating a cleaning utility are tasks that the infection may interfere with, it's a good idea to follow your Malwarebytes scan with other scans that don't require an installation or even an update.
On someone else's PC, download SuperAntiSpyware Portable and copy it to a flash drive. Boot the infected PC into Safe Mode, plug in the flash drive, and run the program. Since SuperAntiSpyware.com updates the portable program every day or two, you don't need to update it before the scan.
For a fourth opinion, try the F-Secure Rescue CD. This is another .iso file from which you can burn a bootable CD. Just boot from the CD and run the scan. The program will try to update its database over the Internet. If it can't, you can download an update on another PC, put it on a flash drive, and keep that plugged in while running F-Secure on the infected PC.
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