Hi. I have recently used Advanced WindowsCare and Ashampoo WinOptimizer Platinum 3 to clean the junk inside my computer.
After that, I tried to access a web site and got an error message. I have visited it 3 days ago, and it was fine.
These type of programs usually do a backup of the things that you delete to clean things up on your computer, you might try finding out where that back up is and have them replace those the files that they destroyed during the process that you think caused the problem.
After you've used the backups try running this program: Spybot Search and Destroy on your computer. And also try this one, Regseeker . Just click the names and the links will take you directly to their download sites. They are freeware programs and so I'm not trying to sell you anything or something. They might take care of the problem by themselves. I love these programs because they don't charge anything to use and probably never will. I've also never had a problem like you described with them. They should do the same thing as windowscare and WinOptimizer and they're free.