System restore doesn’t work, I do not have a prior restore point and I need to remove/change some registry values. I found what to change and what to delete but the directions tell me “restore registry entries to their previous values” what does this mean? Is there a site where one can find what the registry values were?

Everything I click on is real slow, and I have high speed internet, should I do a registry clean up, and if so, how do I perform that action?