I am certainly not very knowledgeable when it comes to PCs but I can tell you that I installed the game fine at launch - clocking up to about 300 hours of play before a patch (I believe some time around March?) caused some issues with the in-game lighting and shadows would flicker like crazy, along with some rather strange shapes in the sky. This was initially what caused me to stop playing because I could not seem to fix it, even after removing all mods.
This week though (a year after launch) I thought I would give it another shot. I completely removed Skyrim from my system (all traces) and reinstalled after upgrading my graphics card drivers. This fixed the lighting problems (huzzah!), however, shortly afterwards my PC shutdown.
It has continued to do this every time I try to play Skyrim for more than 7-10 minutes. I have tried various things such as editing some values in the .ini file (which were suggested on some other forum), installing slightly older drivers for my card, re-installing, etc. (nothing overly complex I know; I really don't know what else is safe to screw around with which is why I thought I had better ask).
My PC specs (the same ones I have previously played over 300 hours of Skyrim with, with absolutely NO problems):
Dell Inspiron 545
Intel core Quad CPU, Q8300 @ 2.50 GHz
4GB RAM
Windows 7 64bit
My Video Card specs (same card too, no changes asides from upgrading the drivers):
NVidia GeForce GT 220
Driver version: 306.97
DirectX 10.1 support
Graphics clock: 615 MHz
Processor clock: 1335 MHz
Dedicated Video Memory: 1024 MB
If anyone has any sort of advice or solution that would be amazing. I hope this is ok to post here, thankyou for your time.