and welcome at GSFs. Main question: What kinda data are on that stick preventing it from a complete fresh formatting? But let me get an impression about your computer and installed security programs:
1.: What operating sysem are you running and got it kept up2-date by regular monthly MS-Patchday updates?
2.: Is an Antivirus program installed and what its its name?
3.: Are the signatures kept up-2-date?
Here are some links how to disable the Autorun function to prevent any infection of your computer via USB devices
Please answer these questions BEFORE we're going on, kay? If you wanna make sure your system is clean get over to our HJT section and follow these instructions please.