Hey I tried what you said and the pc didn't even start back up unless i unplugged them both completely, what should i do?

What did you do? Nothing Zimbo suggested would have caused your PC not to boot. Re-check all your connections. Make sure you set everything back to the way it was ie: primary hard drive as master on IDE 1 and CD rom as master on IDE 2.

I'm having exactly the same problem installing a dvd-writer, and just like you they only power up with the IDE cable unplugged. Even putting everything back the way it was before I put the dvd-writer in doesn't work. I also had the moment when the hdd wouldn't boot in, but I unplugged that IDE cable and put it back in, and it worked again. Does yours boot up when IDE cable is in disk drive,s because mine won't (prompts me to put in boot floppy).

Frustrating, isn't it?