I'm using a dell D600 - I have absolutely no issues with it while just surfing etc.

Here is what I'd do

Upgrade the memory to 2GB (2x 1gb sticks?) (newegg.com - like 30 bucks)
Upgrade the HDD - 500gb is $110 on newegg (WD Scorpio Blue)

Put in Windows XP , NOT VISTA - and you're done.

It should be lightning quick and you've barely spent any money. If you ever upgrade your laptop, take out the 500gb HD and throw it into your PS3!