Question : Problem: Can I use a new 200GB EIDE internal hard drive on an old (3+ years) IDE PC?

..Well?  Can I?
Thanks.

Answer : Problem: Can I use a new 200GB EIDE internal hard drive on an old (3+ years) IDE PC?

Maybe.

It depends upon whether or not the BIOS in your older computer supports an IDE drive that is that large.  If you update your BIOS first, then the answer is probably.  Go to the website for the manufacturer of your motherboard and look for bios updates.