so double click on Electronic Arts, then on 'the battle for middle-earth' hopefully you should see a folder in it called 'ergc' or something similar, double click on that, and in the right hand half of the windo you should hopefully see a single file (probably called '(default)', that is where it keeps your serial number, so now its a simple matter of right clicking on it, and pressing 'modify' you can then edit it i usually just change the last letter on the serial number. In the next list that opens double click on 'Wow6432NODE' (it should be at the bottom), you should now be seeing what basically looks like your program files just listed out in alphabetical order. double click on the one called 'HKEY_LOCAL_MACHINE', it should then expand to reveal 6 sub-headings, double click on 'SOFTWARE'. Once 'run' has opened, type 'regedit' and press enter, a new window should open, on the left there should be a list of the main windows registries. Go to the start menu, then to go to 'run' (in vista you just type 'run' into the search bar and press enter). Im not sure how different it is in XP, but in vista the following method usually works: