I also had the same problems ...
but you should not blame nForce for your Boot hassles..
To get R.H8.0 grub work,
Install R.HL8.0, ***with a boot floppy***.
goto gnu's site, download latest grub(3.0 i believe),
boot in to Linux with boot floppy
copy the downloaded rpm to some dir of your machine,
update existing grub
rpm -U grub-whatever_latest_version.rpm
Now, assuming your boot parition lies on the HDD partition
reboot, it should work