I consider 256MB to be the minimum amount you want to be running XP with, 512MB if you want decent performance.
Generally speaking, every version of Windows is slower than the last, due to feature creep. Microsoft is still stuck in a 1980s business mentality of the pre-Internet age where it just wasn't really possible to download a bunch of small programs for specific tasks. That's a gross oversimplification of the matter, and it completely ignores several important factors, but you get the idea. More features means slower performance on any given bit of hardware.
Adding RAM to the HP system will certainly help, but there will still only be so much you can do. So don't expect any miracles, because they aren't coming, but you can improve your situation.
I have an HP Pavilion xt963 and I hate it..It takes 10 min to start up, It has 40 gb hard drive..128memory..I wanted to know if its possibly the problem?[the 128 mem] For Win xp home,isnt the min. requirements,256? This comp was givin to me...with a burned out fan..so I just stuck a little fan in it..and it works..I have done all the cleaning..all the virus checks..deleatde all the programs.....still sloooow! Should I invest in another mem stick??!I have teenagers!! And they want to download all this stuff on MY IBM!!!I want to let them have this HP so theyll leave my ibm alone..Is there a way to make it fast? Or is win xp normally slow?Iv never used HP or XP before...[only IBM and win2000 pro]....any advice? thankyou!...jiller