My computer is only used for about 5 hours out of a 24 hour day and I do a "cold shut down" every night.

When the BSOD occurs, there is usually text that describes what it "thinks" caused the failure. Sometimes
the text isn't very obvious.
Try using Memtest86 and run a RAM memory test on your system. See if it produces failures.
If there are no failures, at least it'll rule out bad memory.

 

When you get a blue screen, take note of the "0x................" errors. You can google those to get an idea of what's wrong. I generally take a photo of the screen (make sure it's high-quality!) so that you can google the exact numbers once you get back to a working computer.

Usually the most common errors are bad RAM, bad Hard Drive, and bad software.