Q: To streamline my PC's storage of programs and data, I wanted to erase 100 gigabytes of what I considered junk files, some of them noncritical parts of Windows 7.
It didn't go well. When I tried to delete some Windows files, I got an error message about "Trustedinstaller." I didn't know what that meant, so I downloaded a non-Microsoft program called "Unlocker" to delete the files, but I may have gotten a virus by doing so. Then I found a Microsoft help website that told me to use a command called "Takeown," which did allow me to delete the junk Windows files. What happened?
Also, how can I rapidly back up other files to an external drive? With Windows, it takes hours.
R. Schwendler, Lake Wales, Fla.
A: You've encountered the technology Microsoft uses to protect Windows files from accidental deletion.
The protection works by having Windows assign "ownership" of its files. As the PC user, you "own" most of the files on your computer, which means that you can change or delete them at will. But Windows assigns "ownership" of Windows files to an imaginary computer guardian called "Trusted Installer." Before you can alter or delete those files, you must change their ownership from "Trusted Installer" to yourself. Directions are at tinyurl.com/ybc577v.
The "Unlocker" program you downloaded, and the "Takeown" commands you got from Microsoft, will accomplish the same thing. Experts say Unlocker is safe, but that some optional software with it may appear to your security software to be malicious. It might be best to avoid those options. See tinyurl.com/mnwmrl.
You can accelerate your backups to an external hard drive by using some non-Microsoft copying programs. See tinyurl.com/9yqdym.