Update: Thanks to all who helped. I gave up and am going to re-install. Not the end of the world, no files will be lost :-) This time will be backing up grub haha. Thanks again, I really appreciate the community's help on this.

I was going along fine when the new pae kernel came down, and it had some bug where the sound was all messed up.

So I used startup manager to choose the older pae kernel and rebooted. But startupmanager must have fuXXored my grub.

When I re-booted, I get thrown directly into memtest and thats it.

I tried to re-install grub using the live disc method that I found in many places. That changed something so I get a prompt and the message: "GNU grub version 1.99 ubuntu. Minimal BASH-like editing is supported. Type help for complete list."

But then I tried the live CD fix again and now am back at the memtest...

What can I do to get my system running again?

UPDATE: Just to be clear,when I start up I get a blinking cursor in the top left, and the word 'ON' in the middle of the screen. Then, after a good minute or two, the memtest starts.