Here're some things to try
Get your antivirus program up to date and boot into Safe Mode. Note that some viruses can hide themselves from your antivirus program in normal mode, so you really need to scan in Safe Mode. To get into Safe Mode when you first power up, hit F8 about once a second until you get the menu and select Safe Mode. Then run a full system scan.
Microsoft has suggestions and offerings at
MS forum moderator Keith has some suggestions along this line at