Help... Can't boot!

[John Aldrich]

I was using Fedora Core 6, just fine, but decided since it was so out  
of date, that I'd upgrade to Fedora 10. Now, for some reason, it won't  
boot. It keeps saying "Unknown Partition Type 0x5".

This is the same *exact* system that was working with Core 6, all I  
did was install over the old version (except for "/home" and a storage  
partition.)

I'm using X86_64 where before I was using i386, but that shouldn't  
matter, should it?

All data drives are IDE/PATA, but I'm installing off a SATA DVD ROM.

HELP!!! I need to get this up and running as it's my primary desktop  
machine. I am stuck using my wife's XP box until I can get it back up  
and running! :-(