Burner suddenly stopped working

I was burning a CD the other day and it went off without
problem. As soon as that CD finished burning, I put in
another CD to burn another disc.

When I tried to burn the second disc, the drive would spin
up...but never write.

Nero gives a very non-descript error message that just
says the disc didn't burn.

Simulations work...burning doesn't.

This, mind you, happened on my OLD computer which
was an athlon 1700 with 256 mb of ram.

I upgraded my computer to an Athlon 64 2600+ and
bumped my ram up to one gig. Also replaced the
motherboard. XP was reinstalled to accomodate the new
hardware.

Essentially new computer...same problem. I should also
add that I just purchased a new DVD burner yesterday and
still have the problem.

The drive reads discs which is great and all, but I can't do
any backups of any kind...which isn't so great.

I have Nero 7 and also installed the mediocre software that came with the burner.

I also replaced the IDE ribbon when I upgraded my computer.

All right, so I can't remember what processor I have. Its an Athlon 64 3200+.

Doubt this makes a difference, but just to be safe.