Ubuntu 7.10 crashes after loading from CD

I ran Ubuntu off a disc last night. Worked perfectly. (UBUNTU FTW! LINUX ROCKS!)
Then today I gave a friend the disc I originally burn't as I knew it worked and wasn't a bad burn. And so I tried ten minutes ago to use my duplicate disc. After loading Linux presents me with a huge cross-hatched colourful screen and freezes. The screen looks different each boot.
So I thought it must have been a bad burn, and so burn't another in Windows. Same error over and over again.
I've tried the safe graphics mode as well, but it just freezes.

My hard-drive is NTFS 74.5 GB, I'm running XP pro SP2, a Pentium 4 2.8 GHZ processor and I think half a gig of ram. I do not have a graphics card.
Also note, as the title says, I'm running it off the cd, not installing it.

New problem

All I needed to do was set the VGA settings differently, and now I have installed the wonderful Linux!

But a new problem arises. I've made my windows partition too small, and now I can't find the partition manger. Can someone please tell me where it's located so I can resize the partitions on my hard-drive?

Oh and now linux had decided to stop me from editing the grub boot file. I needed to because all of a sudden It's removed XP from the list.

root@AFKlinux:~# gedit /boot/grub/menu.ist

(gedit:6755): GnomeUI-WARNING **: While connecting to session manager:
Authentication Rejected, reason : None of the authentication protocols specified are supported and host-based authentication failed.

open up a terminal window,

open up a terminal window, sudo cfdisk, if this is not what you want you can download gpart.