Is there a piece of software I can install on my Ubuntu installation (10.04) to stress test all the hardware on my computer? I understand I can download a specific disto to do this, but I would prefer if I can simply download the software and use it on my current installation.
There is a well known option on the live cd where you can "stress" test your memory (fourth option in the menu):
This will have you end up into something similar to this:
This image actually is showing bad memory as you can see. If this shows up for you too you can assume those crashes to be caused by memory. If not please update your question ;)
Oh and checking memory can take up a lot of time. And when I say a lot I mean a lot ;)
I never used it but I know that this is probably what you are searching for.