Kernel panic!

[John W]

I am running RH7.0 on an AMD k6-2 500,64MB,15G Western Digital udma 33 ,Asus
P5a mobo,s3 vid card,ensoniq sound card.
I ran  #hdparm -c3 /dev/hda to change to 32bit I/O and then logged out of
root and back to user. When gnome came up it froze and nothing would back it
out of X and without knowing how to get it to reboot I had to reset the
box(I'm sure thats the problem) :(
I get the following error after autorun'
ext2-fs error (device ide0(3,7)):ext2_check descriptors:
block bitmap for group 1 not in group (block 0)!
ext-fs:group descriptors corrupted!
invalid session number or type of track
kernel panic:VFS: Unable to mount root filsystem on 03:07
Any help greatly appreciated!!!
John