As is often the case, there's more than one possible cause. The non-paged area of your memory is a section of the RAM that's not backed up on the hard disk. It's reserved for vital tasks. Either your RAM is not working properly or some other program is interfering with it.
First suspect would be your RAM. Try removing and reseating it. Even if the cause is poor contact at the RAM slot, from many practical experiences with many computers, I find that just pressing the RAM in the slot often does not work. It's best to remove the RAM, clean the contacts and insert it again.
Another possible cause is your gfx card driver. If reseating the RAM does not work, try uninstalling and then reinstalling the nVidia drivers.
If neither of these work, test your memory with memtest86. If you're not familiar with memtest86, I described how to use it and also gave the d/l source a few days ago in this thread:
Need expert advice immediately
There are other possible causes, but these will do to start with.