BartPE should let you play with the offline registry. http://windowsxp.mvps.org/peboot.htm

or there's http://www.mitec.cz/wrr.html I have zero clue on if it works or is even safe to launch. Probably scan it and test run it in a Virtual Machine etc

Don't have access to an actual PC/Laptop atm. stuck using my galaxy10.1 tablet until the insurance company gets there ass into gear and cut me a check.