THIS (http://support.microsoft.com/kb/308421) is what you need to have a read of then!

You haven't said what OS you have. We need to know in order to help!

No problem! There is absolutely no guarantee that the idea will work. Even if it does, it wont work for very long.

One thing that can work for a while is to put the faulty hard drive into a resealable bag and stick it in the freezer over night.

From now on, always back up any data you don't want to loose.

It does indeed sound like the hard drive has had it. Replacing it may be the only option.

You could try downloading memtest via google. Run it for atleast 7 passes, any errors at all and the...