I hate to post huge, long tech problem as my first post on a board, but I'm at my wit's end. Here's hoping this is in the right forum. The system is about 3 months old, it's from an online builder. Specs are: Pentium D Dual Core Asus P5ND2-SLI Deluxe mobo 1 x Geforce 7800 GT 1 gig of Supertalent at 667MHz (single stick) Soundblaster Audigy 2 (added by me) Hauppauge PVR-150 (added by me) 2 x Western Digital 200GB SATA II hard drives Lite-On 16X DVD+/-RW Win XP Pro (updated) Here's a history of the problem. At first, all was fine, except I would get occasional USB mouse problems where my cursor would disappear and I would have to unplug/replug the mouse. Then about 2 weeks ago I was playing Oblivion and kept freezing and having to hard restart. When I did, the machine would boot in 800x600 with 4 colors, and no drivers loaded. I'd reinstall drivers and the next crash would do the same thing. I was also getting intermittant BSODs that referred to nv4_disp.dll. Bad Pool Header and Page Fault in Non-Paged Area. A Memtest gave 20,000 errors in about 5 passes, so the builder sent me a new DIMM. After that the video problems went away, but I was still getting the BSODs. I clean installed XP, and checked my hard drives for errors but they kept happening. I used the MS debugging tools to look at my minidumps, and they gave me this: PAGE_FAULT_IN_NONPAGED_AREA (50) Invalid system memory was referenced. This cannot be protected by try-except, it must be protected by a Probe. Typically the address is just plain bad or it is pointing at freed memory. Arguments: Arg1: f000e2db, memory referenced. Arg2: 00000000, value 0 = read operation, 1 = write operation. Arg3: bf9f206f, If non-zero, the instruction address which referenced the bad memory address. Arg4: 00000000, (reserved) (I don't have the needed six minidumps so I'm just posting that as a quick example) My builder had me switch motherboard drivers from the NVIDIA Nforce4 SLI edition to one called NVIDIA AMD/Intel x16. They said my board would prefer one or the other, and that if this didn't solve it I should ship it back. I uninstalled all nvidia drivers through control panel as instructed, rebooted, installed the new drivers and then my video drivers. That didn't seem to go well; I got spammed with "System has recovered from a serious error" after rebooting, and had to click it away about 19 times before I could reinstall drivers. The BSODs then went away, except that now the machine shuts down randomly every ten hours or so. I say random because it's done it when I was asleep, as well as when burning a DVD and installing a game. After shutdown it won't post back up for about 2 minutes, and always has to be unplugged and then hard reset. So that's where it is now. My builder will want me to ship it back, but my warranty doesn't cover shipping after 30 days. So I want to do everything I can to make sure it can't be fixed here, but I know just enough to be a danger to myself. The help I'm looking for is basically, how can I troubleshoot this before giving up and RMAing? I also want to mention that I have had concerns about my power before (my ex always thought that we had dirty power because she had to RMA 2 separate combos of mobo and processor when building a system in this apartment). My last system also just ... died, stopped booting one day. The board went belly up. I do have a quality surge protector, but I don't have a UPS. So I'm wondering if my power did this to me, and how I can check that. I'm also wondering if it's a problem with the hardware I added to the system after receiving it, or if it is the power supply. Anything that could be fixed on my end is better than shipping it back! Anyway, sorry for an incredibly long post. I'd really appreciate some advice from people that are more experienced than me with this kind of thing.