Ok, step by step.
1) Turn on the laptop. When you log in, is the start button a green rectangle rounded off at one end, and does it say 'Start' on it? If no, proceed to step 3.
2) Visit the Speeding Up Windows XP thread here: http://www.computerforums.org/showthread.php?t=29085
3) CAUTION: Do not do this until you have backed everything up!
If your start button is a big transparent circle, or if you are not satisfied with the thread for some reason, back up all of your files, and do a clean install of Vista (IF and only IF you have a Vista disk). If you do not want to do this, or your computer is still slow, proceed to step 4.
4) To to www.crucial.com
, and run a system scan. It will give you options to upgrade your RAM (buy a new stick or two). If you want your computer to speed up significantly, buy the advised RAM.