I have a 2 year old Compaq computer. Does it take pc100 or pc133 ram?

Answer 1

My educated guess says that it will use anything between PC2100 and PC3200 memory (DDR). I doubt very much it is DDR2, that was introduced very near the end of last year and really got off the starting line this year.

Run the Crucial Memory Advisor to find out, http://www.crucial.com/store/listmfgr.asp?cat=RAM

Answer 2

If you bought it new two years ago, it takes neither of those, it will either take DDR or DDR2. Post you model number and we can tell you for sure.