This requires a little command-line work
step 1) When your computer first presents the GRUB menu, press 'e' when you have Red Hat selected. it will give you a screen with something like
Code:
root hd(0,0)
kernel /boot/vmlinuz-2.4.22-ntpl root=/dev/hda1 ro
step 2) when you have that screen, select the line that mentions the kernel and press press 'e' to actually edit the kernel parameters.
step 3) type at the end of the line
which will turn off DMA functionality but still give you a working but slightly slower system.
step 4) press 'b' to boot linux .
if all this gets your system running then at the login screen login as root and edit the /boot/grub/grub.conf to add the nodma tag to your kernel parameters.
HTH