AUTORUN.INF virus. Is it in my system? How to check?

Start ->Run->(Type)Command
Type CD\ in drive C to go the root directory
Type DIR /AH and press ENTER key.
This will show all hidden files in drive C.
If you could see "AUTORUN.INF file" and "Recycled folder", then your computer is infected.

How to check it's in my USB?
Try the same steps to your USB drive and check if your USB stick contains the Recycled folder and AUTORUN.INF file. If it does then your USB is really infected.