To keep you computer run smoothly, you will have to perform regular maintenance. Disk Cleanup Utility enables you to delete files on your hard drive that you may no longer needed and deletes those files on permission. Further more, freeing up space on your hard drive, using Disk Cleanup on regularly can notably improve system performance.
To access the system clean up utility;
click Start, select Programs, select Accessories, select System Tools, and click Disk Cleanup
Or using Windows command cleanmgr
click Start, click run and type cleanmgr in the box and click ok.
Or access from My Computer interface
Click Start, click on My Computer, right-click the drive to cleanup, click properties, and click Disk Cleanup icon.

Once you run system cleanup utility and the drive analysis is complete. List of file categories will be presented for you to select and delete. You can select all to delete all not needed files or you can select and delete only types of files you want to empty. Disk Cleanup utility will only list junk files such as downloaded Internet content (cache, applets, ActiveX, etc) , recycle bin files, log files, backup files from for previous operating system, offline files, compressed old files, and etc. It will not list required user or system files.

In addition to disk clean up utility, you can also delete cookies, and temporary Internet files using your browser.
To delete Cookies using Internet explore;
1. Open the Internet Explore and click Tools
2. Click on Internet Options
3. In the Temporary Internet Files section, click delete cookies button to clean up the cookies or delete files button to clean up the temporary Internet files.

By definition, Cookies are information saved on the system by a browsed web site.

The Clear History button empties the history folder. History folder holds shortcuts to visited web sites and holds number of days specified in the Internet option. 20 days by default.

You easily check amount of space available on your hard drive for future use and the amount of space already used. You should always now your hard drive space availability before you buy new software to install.

To check your hard drive space
1. Double click My Computer icon on your desktop or click Start and My Computer
2. Right click the drive to check (eg: C:\)
3. Click properties and Local Disk (C:) properties window showing on the left picture will popup


Other ways of accessing Local Disk Properties
1. Right click My Computer icon on the desktop or on the start menu and click explore.
2. Right click local disk drive and click Properties
OR
If you select Details from the View Menu on My Computer folder, that will also display drive size and available space.