But the story sounds like a broken machine. Your questions sound as if you want a course in computer repair or for a STEP BY STEP HOW DO I REPAIR MY BUSTED PC?

There are plenty of web sites about PC repair but in your case it sounds like the basic IDE RULES are something you should research. All this is on the web but some dislike reading and learning then DEMAND others re-write the answers or content. Please use the ready and easy to find content or you'll end up at a repair counter or buying a new machine.

In fact, why not look for another machine? That class machine is often found for free on the free area of Craig's list or FREECYCLE.

-> If I were to guess, you didn't follow the rules on how to configure IDE drives, cables, jumpers and may have a dead hard drive.
Bob