i borrowed a friend my ipod only for him to return it in a state where it no longer boots,and comes up with a icon depicting a
folder and an exclamation mark.what do i do?

I suggest you go here: www.apple.com/itunes/download and get the latest itunes software. Install it and hook your ipod to the computer. start itunes and it should give you an option to restore your ipod (requires you to be online). This process wipes everything on the ipod (there is no other solution), it might take some time to finish (depending on the speed of the internet connection).

First thing to do is if the ipod is an original ipod not china ipod, if the ipod is original, get the original data usb cable and connect to your PC, Note, you must have itune music application on your PC then connect your original ipod it will detect a new installation file from the itune application follow the instruction and repair. Note: you must have internet access to do this. Good luck

Apple Inc are some nasty pips
Something similar happened to me, it was a Red "X" that shows up . .
I had to restore, and upgrade the firmware. . .

Downloaded 60MB for firmware update and lost 120GB of Data . .

Go the Creative way!
I'm enjoying my new player or infact, try Zune by Microsoft!