VirtualBox causes my computer to crash.

[TBOL3]

Pardon me if this in the wrong forums, I didn't know if it went in the general, or Linux specific forum.

Anyway, I'm currently using Ubuntu 8.04 with Virtualbox 3.0.2. I'm trying to run Ubuntu 9.04 as my guest. I got the system installed, all of the updates done, and I even got the guest addons put in. Because I'm using this to eventually install Linux From Scratch, I also downloaded all of the software for that. Now, for no apparent reason, whenever I try to start the virtual machine, my computer crashes. It gets to 97%, and poof, my computer turns off, a second or two later, I see the boot splash, and my computer is starting up again. I've tried this several times, with several different kernels (all 2.6.24), but I can't figure out what the problem is. Because my computer crashes, I can't really see any error messages.

Thank you very much for your help.

[TBOL3]

Okay, I got to the VM without it crashing my computer, sort of. What i did was just dump the current state, and started a new session (although I did take a snapshot before I dumped it). Still, would any of you know why it did this? Thank you.