Windows stuck whenever pressing anything

In August I just bought my new computer, and I kept using Windows ME until, october, I fomatted Windows ME and installed Windows 2000. I formatted my computer a lot of times from October to November the 1st. But After the last format, everytime I get into windows, if I press anything or do anything, the computer will just get stuck and I HAVE to use the reset button, even the CRT ALT DEL won’t work!!! Please Help I really want my other computer back as soon as possible!!!