1. I bough a junk flash drive from eBay which can't boot + i screwed it up by trying to be recognized as local disk! so its useless, i will be buying a new flash drive.

If you are using BackTrack3 + changes from USB without any problem, can you tell me which USB, you are using? I will be buy the same one.

I'm after 16 GB stick.

2. If my PC can not boot from USB, is there a way i can make it boot from USB?