You might want to try running the new version of the free Recuva...
Otherwise, you are probably going to need to do a clean install to make yourself look like a Hero to your sweet young friend... Once the Registry is screwed up, it is damned near impossible to fix... Remember that if all components of the registry were printed out, it could be as much as 600 pages... way too many things to fix, without breaking something else important.
There are NO quick fixes for a registry problem. Unless you used a version that has a restore section that saves the old removed lines.