Wel, it's not a simple thing and you have to be VERY careful when editing the registry, but, in essence, it's mainly about searching for the name (or parts of the name) of the software / company from the regedit.exe's menu, then removing the keys / "folders" that the software created (after uninstalling the software, of course). It would take a while, and you should only do it if you're confident that the removed key is indeed what should be removed.However, I did not check Registry as I don't have clear idea of where Rainmeter's registry would be. So if you can help me on that, it would be awesome.
P.S. Sometimes, some software also leave traces on the hard drive, e.g. folders or files that the uninstall process doesn't remove. They should be deleted as well, for a proper clean uninstall. Normally, there are uninstallation tools (like, say, Revo Uninstaller) that do all these things, but for that to work, you'd have to "record" what the software does when installing as well, with the help of the said uninstaller.
Statistics: Posted by Yincognito — Yesterday, 4:49 pm