Sorry to say, but its time for a new one if its more then 5 years old.
Dont buy best buys "INSIGNIA" brand, this $600 sony knockoff has given us a ton of problems over the last year, and has developed a strong plastic odor... wonderfull
We had a gateway that we bought in 1998, and put out of use in 2004. It had 64 MB of memory, and a P2 processor... Good stuff back then, crap now. I couldnt get it to run faster after I did a format, and loaded the memory up to 128...
New computers can be had for $600ish if you stick with a known name brand, and dont need a moniter and supporting stuff (printers, speakers, keyboards ECT)
Softwares $$ though
~Nate