Sometimes, it might not easy to totally do away from accepting external flash or memory card. There is what you need to do when you notice that your PC is misbehaving after using external drive or cybercafe.

Step 1
click start.

click control panel

click performance and maintenance

click system restore

select restore my computer to an earlier time

You will notice that some days are bold, that is the restore point( restore point means return your computer to former status

select date( bold date) that is behind the day you use the virus flash (eg if you use the flash on 20th November, 2012 select 12 or 17 November

click next and follow the wizard.

Your computer will restart and restore your computer to earlier position.

This will not affect your file like Ms word, excel coredraw etc.
Note: your installed program earlier than the date you chose will be remove.

You can undo your system restore.

This logic has safe me from a lot of trouble encounter using unavoidable flash as a web developer.

Hope you find it useful