The moral of the story is, I better stay away from attempting to mess with this stuff. The computer was made in 2009. I was getting a daily BSOD without doing anything on the system (Windows 7 Ultimate, 64 bit), i.e., just sitting idle at the "User Selection" screen. Even though game play was fine, Microsoft Telephone Tech Support told me the crashes were caused by a malfunctioning graphics card. Every replacement card I looked at required more power then what I have.
HOWEVER, it's been about three years since the tower was opened and cleaned and, since I had to open the tower to find the specs of my power supply, I vacuumed and cleaned out the internal components. There didn't appear to be a lot of dust yet, in the four days since I've cleaned it out, I havent seen the BSOD even once. It used to be a daily event, remember.
So I'll wait to see how things go, I'll wait until things get worse, then I'll buy a new computer.
Thanks for the help.