I had a laptop some time ago that was doing this. Does anything cause it, or does it just do it when it fancies?? Sounds to me that you have a virus or some kind of nasty that's causing the machine to hang - hence the BSOD. The laptop in question belonged to a 14 year old boy who didn't care what he was doing online or what he was downloading!!
It might not work on your system, but try this - it worked for me.
1. Get hold of a copy of the software at the following url.
http://siri.geekstogo.com/SmitfraudFix.php
2. Completely disconnect from t'internet (unplug the modem, or turn your router off, whatever you need to do to ensure you are NOT connected to t'internet). It's not crucial, this bit, but I do it because I get paranoid!!
3.Boot into Safe Mode - to do this, either F8 as soon as you turn the machine on - keep pressing it til the machine does something, it's hard to do it in exactly the right place!!
If you cannot get into Safe Mode this way, try Start>Run. Type msconfig, hit enter. Click the BOOT.INI tab, and select /SAFEBOOT. Then restart the machine, and it will boot into Safe mode.
4. Now, run SmitFraudFix.exe. Select the option to "Clean" (if memory serves, it's option 2).
5. Let the tool do it's thing completely. When it asks you if you would like to clean the registry, press Y. I believe it will shut when it's finished, if not, pressing Q will do it. Now, assuming you had a desktop wallpaper before, (picture of your kids, partner, mam, whatever) your screen will now be blue in place of it. That's how you know it worked. If the tool left your wallpaper there, then there was nothing that it needed to remove.
6. Whilst you're in safe Mode, and disconnected from t'internet, it makes sense to run a complete virus scan. It may take a few hours, depending on your system, your AV software, and how much system resource it devotes to running the scan.
7. Now, your antivirus has finished, and done whatever it was gonna do with whatever nasties it found. (if anything at all)
8. Reboot into normal mode. If you did it through MSCONFIG, you will need to go back to the BOOT.INI tab, and untick /SAFEBOOT. If you did it through pressing F8, then a normal reboot will do it.
9. Reconnect to t'internet. Get hold of a copy of SuperAntiSpyware from here.....
http://www.superantispyware.com/download.html
10. Install in the time-honoured fashion, and make sure it's updated to the latest definition file. Then run it and let it do it's thing.
If this hasn't worked, you've lost nothing, it will DO NO PERMANENT HARM to your machine. It's just cost you half an hour of your time. There may be easier ways of doing what I've just told you, but I've done this on several machines, and it's always worked for me.
Good Luck.