I know it can't infect my laptop, but the viruses can't be left on there. The one that forced me to format was corrupting all the data, and since I go from one class to another it gets to infect the next computer I use.

"You need to format the stick as MS DOS format (FAT) for it to work on both a mac and PC"

It was working on both before, but now it won't work on either and I don't know how to format or anything. The stuff I've done so far has been following directions I've found on other posts, I have just enough computer intel to get by, but not enough to know how to do most stuff without step by step instructions since I tend to learn only when I need to do something.