Tech might hav been wrong, buy something like this;
Plug it in via USB,
if you can access your data then you need to transfer your files to your new HDD - format the old one (deleting Windows Vista) then transfer you files back. Plug the HDD into the computer all should be good.
if you carnt access your data;
..................run some file recovery software on the drive.
.................if that don't work you drive is corrupt and you'll need to format it and see if it fixes your problem.
PS dont get your hopes up when something with an HDD isnt simple - is normally bad news
Intel Core i5 2500K /-\ 32Gb 1600mhz RAM /-\ Asus P8Z68/GEN 3
2x 256Gb Crucial M4 /-\ Crossfire XFX HD Radeon 7950 Black DD
Sound blaster Z /-\ yourpcperfect.com /-\ Windows 7 Pro