Thanks for the info, it almost always helps to know the type of computer. I recently suggested to some one that they take the side off their computer and clean out the cooling on their GPU. It was only at that point I googled the model of the GPU to discover it was fitted to laptops !
Going by your first post - the regular report of ntoskrnl.exe - it might be worth your while to run the SFC /scannow command which will attempt to repair corrupted system files such as this one.
To do this you need to run the Command line prompt as administrator. You get to the command prompt exactly the same way as you get to control panel. If you go the Windows key + 'x' route, RIGHT click on 'Command' and select 'Run as administrator'; if you go the charms route, type 'CMD' into the search box, you will see 'command ' at the top of the list of results and again RIGHT click on this. You will now get a black window with white text with, at the end of the text a blinking underscore.
Type 'SFC /scannow' at the prompt (without the ' ') and press enter. If asked if you want to run it, type 'Y' and press enter (again no ' '). Then leave it to run. It can take quite a while to run, an hour or more, so just leave it to do it. When you are quite certain it has finished, re-boot and see what happens.
Post back if the problem is still with you.