Increase your RAM and so system speed

1. Uninstall all useless softwares.

2. Delete temp files go to run %temp% and select and delete all files.

3. To increase the size of freee space on your hard drive and
If you are using windows XP you can use Disk Cleanup in the
Start / All programs / Accessories / System Tools / Disk Cleanup. You are safe to remove any files found from this program.

You can also go to Control Panel and run Add/ Remove Programs. Once the search has been populated you can remove any programs you are familiar with and not using often. Do not remove any updates as they are needed to make your computer work better. Also don't remove any System programs used by Windows.