One of my hard drives sometimes makes a clicking noise and acts quite slow, how can I repair this because I got a lot stored on the the drive and haven't got any way of back-up as of yet?
Move stuff off that drive by whatever means you can. The clicking is the head bouncing off the platter surface and the drive probably doesn't have long to live.
Agreed - buy a new drive, install it as a slave and (using DOS - if you remember it!) XCOPY the contents across!! I had a 'clicking' drive and it got slower and slower and eventually died!
..unless it's merely thrashing due to small ram memory and plenty pagefiling and also in need of a defrag. which is a lesser problem but more of a grinding noise than clicking. Defragged lately? how much ram?