Any problems Ive had Ive always got my brother to fix, but he never teaches me how what or why.
Give a man a fish, and he has food for a day, teach a man to fish, and he has food for a lifetime.
For the first question, it is often possible to put an old Drive into another computer, and have it work. You will, however, need to perform a XP Repair using the XP CD (if you don't have one, your SOL for that method).
For the second question, the short answer is no- as far as that computer goes, it simply isn't POSTing- the problem lies within. Could be a number of problems, ranging from CPU or motherboard, to an Add-in card that the computer doesn't like.