You need to hide the WoW folder, disable "View Hidden Files" under Tools>Folder Options>View. Follow these steps to remove it from the Add/Remove Programs list:
1. Start Registry Editor (Regedit.exe).
2. Locate the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
3. Locate the key to be deleted by locating the key name created by the program. If the name of the key is not apparent, browse through each key and note the value for DisplayName. This is the viewable string in the Add/Remove Programs tool.
4. Using the Registry menu, export the selected registry key to make a backup. Store the .reg file in a safe location in case you need to import it at a later date.
5. Delete the selected registry key and its values. Do not delete the entire Uninstall key.
6. Quit Registry Editor.
7. Verify that the reference in the Add/Remove Programs tool is no longer visible.
Then the obvious thing, deleting all shortcuts referencing WoW.
If he gets caught it's his own fault, don't lecture him about it. Let him learn the hard way, you guys aren't going to change how he feels about it. And no, BARTPE won't run WoW haha. BARTPE runs off of CD-ROMS and provides a Virtual Operating System. Hence why you can't install anything inside the OS, and it requires you to burn an entirely new CD when an update BPE comes out. Unless they've changed there ways recently. But either way the Windows Kernal takes up the entire HD space, so even a new BARTPE wouldn't work since WoW itself needs almost 5 Gigs of space.... so it's not possible, you have to install WoW inside Windows. Among MANY other issues using a VOS for gaming, it's just impossible. Also, the hiding feature of folders WON'T work if someone is intent on finding it. You can enable "Search Hidden Folders" when searching. If in that case, you will need to search for a program, I forgot the name, that will hide it even from that. Even STILL if your dad is a "super IT man" there is 2 more ways he can find out if you've been playing, but he would have to assume your extremely fluent with PC's I doubt he would go that far, assuming he even knows how to access this. For this, I require $15 through Paypal ;-)