which hard drive ? Help needed

[nvvnravi]

I gave previous post where i mentioned my problem.
I tried so many things after that which i think may take pages if i start describing....

Well i have a strong feeling that my HDD has gone.BIOS is also not recognizing.

So can anybody tell me which HDD will be best and suitable for my TP.
My configuration
R31 1.13 Ghz,758 Ram.
I am looking for a 7200 rpm HDD (if that is compatible with my laptop)
also i am looking for memory around 30 or 40 approx.
If i get the then how can i install OS on that .doe sit come with something or what?
i am a new bee in reinstalling new HDD ..

Can i install linspire Ver 5.0 on it .