The computer is almost 6 years old and could easily have just run out of steam.
You can get a very good computer for around $500. I reccommend Dell!
If you don't have $500 for a new PC (which you really should spring for with a 6-year-old computer, as it probably won't take well to anything newer than 2000), I would just reinstall ME and wait it out until you can afford one. Personally, I wouldn't waste money getting a license for a new OS for $100 or more only to get a better PC later on.
