I ran CCleaner yesterday, which eliminated a lot of trackers/junk and claimed that everything was fine. However, the PC is not working as expected, not only it takes longer to start but doesn't recognize the 2nd (internal) hard drive. When I open the Device Manager, the system sees it as an 'unknown device' and, when I try to update the drivers, it claims that the best ones are already installed. I have almost 4 TB of important data on the drive so reformatting is obviously not an option. Any suggestions on went wrong or how to fix it would be more than welcomed. Thanks.