My pendrive got infected last friday. I didn't know that and connected it to my computer. I've tried many things on the internet, but the autorun is still here and has already infected my sister's pendrive.
Try scanning it using Malwarebytes Free linked in the last link in my signature below. Actually I'm surprised that McAfee hasn't wiped it for you. Did you try booting into Safe Mode and scanning it by right-click > select > Scan?