Windows wont read files from or format my external hard drive

i plug it in and the files that were on it wont show up and vista tells me the drive needs to be formatted before i can use it, i try to format the drive and the format gets to the end of the process then i get a message that tells me it cant be formatted. ive tried it on 2 computers now and it still wont work. it dusnt give any kind of error code, just a message.

can anyone help or does anyone have any ideas that might help fix this problem?

have you tried right clicking then selecting run as administrator first.

nevermind, i used my dads old laptop that had Windows XP to do it and it worked fine.