With all the recent forum posts about corrupt Windows updates causing startup issues, I discovered that my WIN 7 Pro desktop would suddenly not respond from sleep mode. Restart would just get stuck on POST, and would not boot into WIN 7.
Not too concerned, as I'm well backed up. My full system image backup is less than a week old. And my personal data such as browsers, email, files, and photos are all backed up and encrypted at minimum once a day. All thanks to free or open source backup/sync software set to run automatically.
But was a false alarm, as I noticed POST would not get past USB bus checks. Turns out, my Logitech mini wireless keyboard/mouse transmitter was slightly ajar in its front USB slot. Pulling it out and putting it back in allowed POST to complete, and load WIN 7 normally.