I managed to revitalise an old P4 laptop by replacing its 20gb 4200rpm Toshiba with a brand new 80gb 5400rpm WD Scorpio Blue. Despite the relatively small increase in rotational speed, the newer HDD made a huge difference, with sustained reads about 3-4x faster than the old drive. Made the lappy much more usable, and my brother's been using it on a daily basis.http://www.newegg.com/Product/Product.a ... 6822136129
was the drive I got, fwiw. They also do them in varying capacities upto 250gb. You'll notice a lot of the Newegg reviews talk about reviving older laptops, which I imagine is where 90% of these drives go
A new laptop would obviously be faster, but I would give consideration to trying the new HDD + a fresh windows install. If you're running Windows XP, the 1GB of RAM that comes as stock with the laptop shouldn't be holding you back too badly. If you're running Vista or Win7, different story!