1- Start Internet Explorer, click tools, internet options, then click delete cookies, delete files (check offline too) and clear history, one at a time.
2- Then click Start, programs, accessories, system tools, and then click Disk Cleanup and check ALL the boxes displayed (may take a couple min's).
3-Make sure your Trash Barrel is empty (recycle bin)
4-An additional thing you may want to do:
Remnants of an installation or patch are stored by Windows as temporary files, which can prevent the re-installation or starting of programs. These temporary files are normally created to temporarily store information in order to free memory for other purposes, or to act as a safety net to prevent data loss when a program performs certain functions. These temporary files however can trick an installation program into thinking that the propgram is already installed, or that a patch is installed when the patch has not been applied properly. Because this can cause complications, it may become necessary to delete these remnants to give your system a clean slate prior to launching or installing a piece of software.
To delete your Windows temporary files on Windows XP:
First you will need to delete the standard Windows temporary files:
Click on the Start button.
Click Run.
Type 'temp' into the available text field and click OK.
Click on one of the files in the folder that just opened, and press Ctrl and A to select all of the files in this folder.
Press the Delete key on your keyboard.
When prompted if you are sure, choose Yes to All.
Next you will need to delete your specific logins temporary files:
Click on the Start button.
Click Run.
Type C:\Documents and Settings\<Insert login name here>\Local Settings\Temp in the available text field and click OK.
Note : Be sure to specify your Windows login without the greater than/less than symbols.
Click on one of the files in the folder that just opened, and press Ctrl and A to select all of the files in this folder.
Press the Delete key on your keyboard. You may get a warning about the Perflib file if it isn't 'hidden' as it is in use - say OK. Then change its' properties to hidden and do this again.
When prompted if you are sure, choose Yes to All.
5-Assuming you are still in operation, defragment your drive.
6-Reboot.