To answer your questions:
"Is all the hardware the same as when the computer was new?"
No. Actually, my DVD RW was failing so I replaced it with a new one 3-4 months ago. Haven't had any problems with the DVD RW since and didn't notice anything different until I started getting these messages a couple of weeks ago.
"Were you getting blue error screens prior to this problem?"
No. It just happened suddenly. Although I can hear the fan working extra hard from time to time prior to this problem.
"Do you have any peripherals connected to the computer now?"
No, all is disconnected except for a wired mouse and keyboard.
"Have you added any memory to your computer or any add in cards like sound, TV tuner, etc?"
Other than the new DVD RW, everything is the same.
"Do you know what your memory is and how it installs?"
I have 1 GB (512 x 2) Memory PC2-4200 533 mhz Dual Channel DDR2. It's plugged into the MB directly. Does that answer this question?