If you have installed Win 7 Service Pack 1 and everything is workng fine, you can re claim some disk space by removing the backup files of the service pack.
You can do this either via the command line or using the Disk Cleanup utility inside of Windows 7.
Command Line
open an elevated Command Prompt window with elevated permissions, and run the following command:
dism /online /cleanup-image /spsuperseded
Below is a link to a video demonstrating how you can you can use the disk cleanup utulity.
Posted by mcaffari 
