OS will not boot

I'm installing Ubuntu 9.04 for the third time in two days. After the first install, update manager popped with 200+ patches to install. I told it to go ahead, but one of them (can't recall what it was called exactly, something about linux restricted modules) tripped an error message and the install hung up. I forced the application to quit and restarted the computer. GRUB came up but said it was loading, but the screen went black and the machine froze. The OS never came back.

I reinstalled from the same CD and this time, told update manager not to install the offending patch. I was playing around a little when the update manager popped up again telling me to install the patches which I had previously chosen not to install. I tried to close it, it hung up, and I did a force quit. Today, when I came home and attempted to run my computer, I got the same issue as before. GRUB comes up, it looks like it's going to load, but the OS never starts. Instead, the machine just idles with an all black screen. Not knowing what else to do, I'm reinstalling for the third time from CD. I'm just wondering if anyone else ran into similar issues or knows what could possibly be the cause.