8.10 to 9.04 Upgrade, problem with display.

[archolman]

On Pentium3, i386 hardware, after upgrading 8.10 to 9.04, my display has corrupted. It shows 4 vertical windows, all fuzzy, with a frozen mouse. The autorepair functions in Grub have no effect. Any ideas as to what I can do to get my system back, or how I can roll-back to 8.10? I have a little bit of experience with the command-line, but don't know the code very well, so please include any code I need.
Thanks in advance.
*edit
I have the 8.04 install disc, can I use this to repair the installation, & upgrade again?
I'm using it as a LiveCD to get on here at the moment, so I know that the box is working properly:)

[archolman]

I hope that this helps:

ubuntu@ubuntu:~$ sudo fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x987a987a

Device Boot Start End Blocks Id System
/dev/sda1 * 1 19365 155549331 83 Linux
/dev/sda2 19366 19457 738990 5 Extended
/dev/sda5 19366 19457 738958+ 82 Linux swap / Solaris

Disk /dev/sdb: 1031 MB, 1031798784 bytes
16 heads, 32 sectors/track, 3936 cylinders
Units = cylinders of 512 * 512 = 262144 bytes
Disk identifier: 0xa3c6ba1f

Device Boot Start End Blocks Id System
/dev/sdb1 1 3936 1007600 e W95 FAT16 (LBA)

Disk /dev/sdc: 2038 MB, 2038431744 bytes
251 heads, 62 sectors/track, 255 cylinders
Units = cylinders of 15562 * 512 = 7967744 bytes
Disk identifier: 0xc3072e18

Device Boot Start End Blocks Id System
/dev/sdc1 * 1 256 1990624 c W95 FAT32 (LBA)
Partition 1 has different physical/logical beginnings (non-Linux?):
phys=(0, 1, 1) logical=(0, 1, 3)
Partition 1 has different physical/logical endings:
phys=(505, 250, 0) logical=(255, 209, 44)
Partition 1 does not end on cylinder boundary.

ubuntu@ubuntu:~$ sudo apt-get check -v -u
apt 0.7.9ubuntu17 for i386 compiled on Apr 22 2008 15:19:47
Supported modules:
*Ver: Standard .deb
*Pkg: Debian dpkg interface (Priority 30)
S.L: 'deb' Standard Debian binary tree
S.L: 'deb-src' Standard Debian source tree
Idx: Debian Source Index
Idx: Debian Package Index
Idx: Debian Translation Index
Idx: Debian dpkg status file