Free disk space

[Overnight]

Defragment regularly hard drive : in addition, it allows programs to start faster.
Delete "c:\windows\temp" folder's content.
Delete for each user_profile "c:\documents and settings\user_profile\local settings\temp" folder's content.
Delete "Recycle Bin" content.
Use "Disk cleaning" button in HDD properties window.
Suppress useless programs using "Add/Suppress Programs" tool from control panel.
Reduce disk space allocated with system restore for each HDD : from control panel, choose "System" and "System restore" tab.
Reduce disk space allocated with the "Recycle Bin" for each HDD.
You may use Treesize available in Downloads to identify the "heaviest" folders.