Bad Codecs Bring Down the Curtain
The Hassle: Figuring out why some videos won't play on my PC is my new least-favorite pastime.
The Fix: I go straight to the heart of the matter by using CodecInstaller. It's a freebie (donations are accepted) that looks over my system and tells me which codecs--the programs needed to view videos--are missing. Then it supplies safe, reliable, download sources. If CodecInstaller doesn't keep your videos rolling, try the shotgun approach: Download and install K-Lite Codec Pack, which has almost every codec known to humankind (13 gazillion at least); this freebie comes with a handy video viewer, too.
The Hassle: I recently went 15 rounds with an erratic power button on my PC; every other day or so, it wouldn't work, stalling Windows in mid-shutdown and forcing me to remove the power cord to turn off the PC.
The Fix: Replacing the power button didn't help, but a $10 power-supply tester from PC Power and Cooling revealed that the power supply was a goner. If you're handy (and cautious), try this shockingly easy power-supply testing trick from the company's troubleshooting page.
For people who like tracking down ornery problems on their own, What's Running offers a look at every active element of a PC: services, processes, drivers, and other modules. What sets What's Running apart from similar tools is its clever way of saving snapshots of settings; compare a shot taken when the system was working right with a shot from when it wasn't to hone your troubleshooting skills.