Laptop so slow! (Not ram though)

I've recently come across a Toshiba Satellite Pro A10... its not great (2.5ghz celeron) but it should be a LOT faster.

Originally, the HDD (30gb) was currupted to the point that a fresh copy on windows wont install (when searching for previous versions of windows)... I then replaced it with the exact same drive (30gb toshiba drive) this works as it came from another working laptop.

I then installed WinXP pro onto the new disc, it took 10 hours! (256mb ram)... a lot of the time was taken through the "copying installation files" phase.

When i woke up in the morning, it had finished finally. I stuck 1gb of ram in assuming it needed more, but MSHearts even lags with a gig of ram (it is registering with the OS too). Mobo and video drivers have been installed.... so im a bit puzzled as to why its so slow... its slower than some 486 systems with 3.11 on them, and celerons arent that bad!

any insight would be helpful

thanks

sean