Follow the steps outlined below.

Go to start/run type in regedit and click ok.

Click on the HKEY_USERS branch (to highlight it).
Select File on the menu/Load Hive. Navigate to x:\Documents and Settings\Default User folder (where x houses the Documents and Settings folder). The Default User folder is hidden by default. Open the ntuser.dat file.

For the Key name: type in the word tweakxp (actually you can type in anything) and click ok. A new subkey named tweakxp will appear under the HKEY_USERS branch.

Navigate to

HKEY_USERS\tweakxp\[remaining path to the restrictions/tweaks you want to set]

Add in the applicable values and value data.

Go back to the subkey tweakxp and click on it to highlight it. Select File on the menu/Unload Hive.