Go to start Accessories. Go to system Tools go to desk cleanup. Try to clean up as much as you can. Also try to remove any program that you do not need.

Also remove any programs that you do not use.

IF you have the recovery/restore CD with your laptop. You can try to restore your laptop to the factory settings. you will have to back up any information that you need to keep to your external hard-drive. It might do the trick.

Personally I use a program call CCleaner to remove non-needed/temporary files on my Laptop to recover space.