Highest Priority: Do Not Install Malware Thinking it is Anti-Malware!
You may be typing at the
time the question comes up. In the course of typing you hit the
spacebar and automatically answer the question before you see the
question. Often this means you permanently blocked something you didn't
want blocked, or you allowed something you shouldn't have allowed.
ClamWin is a free anti-virus for Windows. It does not monitor every file or transaction constantly - you must intentionally scan files that you receive or that you wish to test. The advantage to this is that your computer isn't slowed down by excessive constant monitoring. Many reasonable people do not get infected using only ClamWin - IF they can follow the other recommendations on this page.
You can right click any file you see in My Computer or Windows Explorer, and choose Scan with Clamwin. You can also set up a scheduled scan to run at night while you sleep. Don't let the scan to check your whole system run while you work, as it takes up 100% of the CPU. Make sure your computer is in a cool room or put an extra fan or air conditioner pointed at it for a full system scan.
Change your habits to prevent re-infection