Delete unneeded files:

When an application runs, it sometimes creates temporary files. When the application exits, these files are deleted automatically. However, if it terminates abnormally, the temporary files remain on your hard disk taking up the space.
Windows has two utilities for cleaning up your system.
a) Disk Cleanup: It finds and deletes unnecessary files from the hard disk, freeing up the overall disk space.
b) The Desktop Cleanup: This wizard eliminates unused shortcut icons from your desktop to a single folder.
There are two ways to start Disk Cleanup:
1). Select Start >> Programs >> Accessories >> System Tools >> Disk Cleanup. Now in the Disk Cleanup dialog box appeared, select the drive you want to clean.
2)· Open My Computer, right-click on the drive you need to clean and select Properties. On the General tab, click Disk Cleanup.
Either way, Disk Cleanup is possible. A pop up appears for the selected drive showing which files Windows thinks can be safely deleted. Mark or clear the checkbox for each category of files that Windows presents, click OK, and then click Yes.
More options tab is available to clean windows components, installed programs and system restore.(Only advanced users are advised to perform those.) You can run disk cleanup manually:
1. Right-click the desktop and select Properties.
2. On the Desktop tab, click Customize Desktop. The Desktop Items dialog box appears.
3. On the General tab, click Clean Desktop Now. The Desktop Cleanup Wizard starts.
4. Click Next to continue, and then on the Shortcuts screen, mark or clear the checkboxes for each desktop shortcut. Next to each shortcut is the date on which it was last used; items that have never been used are marked by default.
5. Click Next, and then Finish. You're done.
When you finish, a new folder icon appears on the desktop called Unused Desktop Shortcuts. It contains the removed icons. You can open this folder at any time and drag one of the icons back to the desktop.