you have a quick look in your documents, music & pictures folders and clean out unused/unwanted files first.
System restore is a great tool but not usually the right tool to use to free up hdd space :)
If your running on Windows I also suggest running the Disk Cleanup wizard.
Win 7 / Vista : Start -> Accessories -> System Tools -> Disk Cleanup.
Win XP : Start -> All programs -> Accessories -> System Tools -> Disk Cleanup.
Once DC has analyzed the PC it will come up with a set of options. It should be safe to select the following and Click OK to continue removing them.
- Temporary Internet Files
- Recycle Bin
- Debug Dump files (WIN 7 / Vista)
- Temporary Files
Once you click OK Windows will then remove these files from your HDD freeing up some space. Its always a good idea to run Disk Defragmenter afterwards to ensure optimum performance.
Win 7 / Vista : Start -> Accessories -> System Tools -> Disk Defragmenter.
Win XP : Start -> All programs -> Accessories -> System Tools -> Disk Defragmenter.
Select your primary O/S drive (usually C:) from the list and Click Defragment. Wait for the Defragementer to complete (It might take some time :) ) then restart the PC.
Hope this helps