Ok, before we start things off here, I'd just like to start by saying I did do a search for this problem (knowing its a little prolific) and I did find previous threads. However these were either solved by a method that didn't work for me, or were not quite applicable. Basically all I'm looking for is more insight to the matter as I've melted my brain on it to the point I can't think straight anymore. The problem? The infamous nvlddmkm.sys issue. So, it started about 1 month ago after over 1.5 years of no similar issues. The biggest change I can think of that happened was a driver change. However rolling back my drivers hasn't solved the issue, nor has installing various revisions from 169.xx - to the current 180.xx. Every uninstall was followed by a running of Driver Sweeper. I'm pretty sure it isn't software related though because I eventually broke down and did a fresh install of Vista, which only seemed to 'reset' the issue. It still happens though alot less frequent but it is picking back up. This effectively removes drivers from the list of possibilities, unless most every driver release has been faulty, including ones that have worked for other people. Failing drivers, I have run several passes of Memtest being that some have said faulty RAM can be a cause. I have encountered 0 errors on all tests done. Also, I've tried removing sticks as per another solution to change around the configuration and this only seemed to slow down the problem. Even though I know the Kingston memory isn't top notch, I think this effectively is eliminated as a variable. Currently I'm waiting on my brother's brand new 9800 GT to arrive in the mail because he is going to allow me to test it in my system to see if its a problem with the 8800GTX or not. Also, I have the 8800GTX pulled out and cooler pulled off as I was reapplying thermal paste due to some saying overheating is the issue. Slight hiccup here though, for two reasons. 1) I go out and purchase an aftermarket cooler ($50-$70 Cdn) that may not even help if the card itself is the issue. Then I'm stuck with a purchase I can't use on any other piece of hardware I own. I'm not sure of the return policy at the local computer shop but I do know they have a minimum 25% restocking fee. 2) I put the stock cooler back on with a new application of thermal compound, though I'd need to go pick up some thermal tape for the other parts of the PCB that need cooling. I've already tested and theres too much of a gap to use AS5 like I used on the core. If I go with the thermal tape I've done very little to lower temperatures, other than 'refresh' what was originally there, as I had AS5 on the core and the stock tape elsewhere to begin with. There probably wouldn't be enough difference to test the overheating aspect. If the 9800GT doesn't work, I have hit a dead end. I've seen some mention it could even be a motherboard issue, however I have no way of testing this that I can think of. And although replacing mine is probably a damn smart idea seeming it isn't a stellar board, I don't have the money to fling at this system till it works. With that in mind I'd kind of like to be a bit more sure than guess and test. Things that point to a hardware issue: - at times, from POST to Windows Desktop to eventual shutdown, there are constant graphic distortions, usually not changing at all from start to finish. Best described as red or green lines that are static on the monitor no matter what is displayed. BSOD usually follows quick on this one. - constant failures no matter the circumstances, be it My Computer, WoW or any other window open / opening / opened. Things that point to a software issue (because I'm not convinced its not) - switching user accounts can sometimes resolve the issue entirely. If it was my video card frying, why wouldn't it do it constantly across both accounts? - sometimes nothing at all will be an issue no matter the current stress or length of time running. Can change at the drop of a hat though. The fact that most cards in my price range right now would actually be a step down from the 8800GTX or just on par with. Replacing it exactly is straight out due to the odd pricing of ~$400 Cdn for a new 8800GTX. I really don't want to have to buy a new card after looking at those statistics. Though I suppose it shows the lasting power of the G80 chipset. I was wondering if anyone here had any further insight into the matter, any tips or tricks I may try. As a note everything is stock speed currently and has never been overclocked, though I was tempted to start a few weeks before this started happening. I apologize for the long read, I just dumped my brain on all that I've learned on it. I'll probably remember more later but this is good for now. Please help!