Malware if unchecked damages the machine's OS (vista in this case.)
Use system restore to when it worked and take advice from Grif about some free scanners at -> http://forums.cnet.com/5208-6142_102-0.html?messageID=3105025
Good day. I'm using Windows Vista and every time I click a drive or a folder in windows explorer or my computer the first option I'll see is Explore, then Open then Search and etc. To make matters even more annoying when I click Explore it doesn't work as it normally should instead it works as when one chooses the Open option. The Open option as well works in reverse (works as the normal explore option). I scanned my PC (using both Avast and Avira Antivirus) and found no virus. I even formatted my PC and after a few days the same thing appeared again. Can someone please help me?