Major Geeks I think sites like this are the cats pajamas..the bees knees. You can find a ton of utilities etc here to guide you into laptop euphoria. Temps can plague a computer, but did you already check things like, Virus/Spyware/Adware/Defragmenting your drive etc. Have you checked how many process you have running in XP and how much available ram there is? crtl,alt,delte. Having your drive already 66%full will slow things down a bit, but should not be agonizingly slow. Sometimes a swap file is to blame also, but try programs like Adaware SE, spybot s+d,AVG for virus' if you are with out protection. scan for errors, defrag.. basically clean out your closet first. If you've already done that, then you can move forward..
Check out NHC , notebook hardware control software. Sorry for no links, but you should find most of this easily at Major geeks
Over the last 3-4 yrs AV has quadruple in size. If you are using Norton Kill it and move to one of the free services. So you may be running low on resources. It's always better to reload windows every year to cleanup from all of the MS updates. And not every program you load require to be a quicklauch, desktop icon or tray item. These consume resources. Also check your msconfig and see what is not required.