Are you running out of disk space on your hard drive, you can help recover this space by removing unnecessary temporary files, emptying your Recycle Bin, and compressing old files. Microsoft includes a tool called 'Disk Cleanup' that can delete these files with a relative level of safety.
To launch the 'Disk Cleanup' utility, from the Start menu select Programs | Accessories | System Tools | Disk Cleanup. When you start the application, the first thing it will do is calculate the amount of space it will save you. Then place a checkmark next to the types of information (such as deleting temporary files) that you want to delete. Finally press the OK button when you're done.