Interesting afternoon. I arrived home to find my PC sitting at the login screen, as per normal, but when I clicked on my username to log in it logged in fresh rather than into an existing session (indicating that my PC had rebooted).

Once I’d logged in I brought up Task Manager and noticed that the CPU was running hard at 100%. The culprit process was “wmpnetwk.exe” – the Windows Media Player network sharing service. Stopping the service from the Services applet brought the CPU back down to single-digit usage, so that was definitely the problem. Of course, I didn’t want to leave it stopped, because I use it to watch videos on my Xbox 360.

A quick search on the net yielded this post by fellow Aussie Brad Saide late last year. I didn’t bother taking his advice and searching through Media Player’s indexes, because I knew immediately what was happening. A couple of videos had started downloading in uTorrent but the download had been paused by the scheduler. One of them only got to 0.4%, and was therefore showing up as a corrupted file to the indexer, causing it all sorts of problems.

I opened uTorrent’s options dialog and enabled the “Append .!ut to incomplete files” option. Now neither of the files shows up as an AVI to Windows, and the Media Player indexer ignores them.

The point of this is that the CPU running at 100% for the better part of the day had caused my PC to heat up dramatically, and coupled with the fact that the temperature today peaked at just over 40°C, the PC just couldn’t last long before blue-screening and rebooting (in fact, it was lasting about 10 minutes).

The whole ordeal was a bit of a scare – I don’t really want to be in the market for a new PC just yet. Still, it has reinforced this point by Scott Hanselman (coincidence?) that a backup strategy is very important.