1. Create the destination folder for the Temporary Internet Files.
2. Hit START, Run and write down REGEDIT. Press ENTER.
3. Go to the following registry key:

HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Explorer \ User Shell Folders

In the right-panel, double-click the value named Cache and set it’s value to the new Temporary Internet Files folder (assuming the new directory is located on D:\Temporary Internet Files)

4. Make the changes in the following registry key:

HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Explorer \ Shell Folders

5. Close Registry Editor and log off. Log in back for the changes to take effect. The Temporary Internet Files will be stored in the new location which you defined.

6. Delete Temporary Internet Files. The old Temporary Internet Files can be deleted manually by navigating to this folder C:\Documents and Settings\YOUR COMPUTER NAME HERE\Local Settings\Temporary Internet Files.

A good solution to detect and delete the duplicate files from a pc is to install a free and small software, named Easycleaner. I am using it for a while, successfully. The most powerful function you can get using Easycleaner is cleaning the registry. Other things you can do with: delete unnecessarily files and internet cookie files, manage programs starting at startup, add/remove programs (clean install and uninstall!), clear invalid shortcuts and history. Also, Easycleaner give you interesting informations about disk usage. Personally I used it mostly to check for duplicates files.

To get it, go to http://personal.inet.fi/business/toniarts/ecleane.htm and then download files/EClea2_0.zip
You don’t need to install anything, just double-click on exe file and you have open the program. Go to Options / Duplicate files and be sure you have checked, in require section, all four boxes.

My advice:
Be aware to use this software because if you go wrong is possible to lose important files. Be careful which files are you deleting!