Stay calm! Even if you have a big report due tomorrow and it appears that your PC has decided to ruin your career. Solving computer problems needs to be done in an orderly, systematic way. Randomly clicking buttons and changing settings can end up doing more harm than good. If you're feeling panicked, walk away from your PC, make a nice cup of tea, and then consider your next step.
First, don't make changes to your PC that can't be undone. If you're about to change a setting or install a new driver in Windows, make sure you've recorded the old settings or saved the old drivers. Likewise, when replacing an old file with a new one, don't delete the old file. Just change its name slightly by adding a 1—or any number or letter—to the end of its name. (Just right-click the filename in Explorer and select Rename.) If you ever need the old file, it will be right there and easy to find.
Second, never forget the golden rule of troubleshooting: Back up everything, twice! Even after you've successfully fixed or upgraded your PC, it's not unusual to find that important files have inexplicably disappeared.
