External Hard Drive Problem - Keeps Resetting Itself

Problem:

Everytime I hook up the external hard drive it keeps resetting itself, by finding the hard drive and not finding, finding, not finding, in that cycle. I already tried reformatting and reinstalling the O/S of this computer and that has not changed anything. On the external hard drive, I tried doing a complete intense error check, defragging , and checking it for viruses. Right now the only solution I have is to transfer the files from this 320 gb external hard drive to my other 80gb external hard drive and than transferring the files to the computer from there, since the 80gb works and 320gb doesnt. I only do this because the 80gb is one of those old types that requires you to plug in ac power cord everytime to use it, and I have a hard time reaching the power outlet, so this becomes very annoying. If anyone knows anything it might be please let me know, I really hate spending the extra time each time to transfer stuff.



Things to know:

1. The type of external hard drive is:

http://www.newegg.com/Product/Product.aspx?Item=N82E16822136227

2. I have tried it on 2 different computers and both are not giving me the same problem as this computer. Everything is working 100% fine on both these computers. ( both are the same operating system as the one having problems )



Thanks
-Krazed