If you want to increase the space of drive C, you can delete the contents in the following folder:

All files under c: \ documents and settings \ user name \ cookies \ (keep index files)

C: all files under \ documents and settings \ user name \ local settings \ temp \ (user temporary files).

c:\ Documents and Settings \ user name \ local Settings \ temporary internet files \

All documents under c: \ documents and settings \ user name \ local settings \ history \ (history)

All files under c: \ documents and settings \ user name \ recent \ (shortcuts to recently browsed files)

All files under c:\WINDOWS\Temp\ (temporary files)

C:\WINDOWS\ServicePackFiles (backup files after upgrading sp 1 or sp2)

Compressed files under c:\WINDOWS\Driver Cache\i386 (backup files of drivers)

All files under c: \ Windows \ Software Distribution \ Download.

If the system has been upgraded by windoes updade, please delete the following files:

Hidden files starting with $u ... in c:\windows\

If you enable the system recovery function, you can delete the restore point. You can create a restore point yourself, and then delete all restore points except the last restore point you created through Start-All Programs-Accessories, System Tools-Disk Cleanup-Other Options-System Restore.