If your not using the Windows System Restore feature, then why have it enabled?
If you are using it, perhaps you want to re-evaluate how much disk space its using up (which can be several GigaBytes) for saving checkpoints. If you only want to have 1 or 2 good saved checkpoints to restore from decrease the allocated space for system restore to a few hundred meg.
The most common area on a users PC in which Windows allocates a chuck of space for itself is the recycle bin. If you rather have files be deleted instantly and not put in the recycle bin or you want to decrease the space it uses to hold deleted files
– Empty or Decrease your Web Browsers disk usage for Cached files
Every web browser has a preferences or options area to adjust the temporary internet files and cache usage. In this video tutorial we use Internet Explorer as an example on how to save space with an adjustment of the temporary internet files space it uses.
If you don’t know what Hibernation is , chances are you aren’t using it. You might want to disable it to save a few Gigabytes of space that function requires as shown in the video tutorial.
For Vista users you can open command prompt and type powercfg -H off
Windows comes already with a built in cleaner that does simple basic tasks to free up disk space.
To access it click start -> Run -> type cleanmgr -> press OK