I built my desktop about 8 months ago, and initially it worked great. Lately, it's been slowing to a crawl for about a minute and then completely locking up. It doesn't blue screen, just sits thinking and if I leave it for a while (30 minutes to an hour) it eventually comes back. Twice when I hit the restart button it's come back with a black screen (though a full power down and up has brought it back). It doesn't look like the processor is maxing out when this happens (though my ability to get to task manager when it happens is pretty inconsistent). I use this computer for gaming as well as some computationally brutal bioinformatics work.
I had Avast and since that didn't find anything I assumed it just wasn't working, uninstalled, tried BitDefender, also came back clean, didn't like the annoying notifications, so I then switched to MalwareBytes, and still clean, so I'm pretty sure it's not a virus. I've run Seatools as well as chkdisk, both clean, mdsched and memtest, both clean, Passmark's BurnIn for the processor, also clean. I don't know what to test anymore. OpenHardwareMonitor shows my temps all being in the low 30s.
Some other things I've noticed: Windows has a notification for chipset drivers being out of date (even though I've reinstalled them, and they show as up to date in the device manager); my disk utilization in task manager often shows high utilization (90-100%) even though the listed processes only add up to 2 or 3 MB/s, CrystalDiskMark gives normal benchmark values though; I have 8GB of RAM, but my paging file fluctuates between using 4-8GB as well (not sure if that's actually indicative of anything, but I've heard with that much RAM, that the paging file wouldn't get much use); and Event Viewer has some weird stuff there is an event that is just repeated every 5 minutes "The Windows Security Center Service could not stop Windows Defender", and about 10-20 minutes before each crash, there's "Insufficient quota to complete the requested service. (HRESULT : 0x800705ad) (0x800705ad)". I Googled these and didn't find anything useful (a few results about AV software I don't have being incompatible with 664-bit and some results about possible rootkits (but I imagine at least one of those AV programs would've found the rootkit if there was one?)).
Thank you so much to anyone who takes the time to read all this!
Here's the specs if that matters at all:
Windows 8.1 Pro 64-bit
MSI Z97 GuardPro Motherboard
i5-4690K Intel processor
Seagate 1TB Barracuda
Nvidia GeForce GTX 780
(It's built to be overclocked, but since I haven't got around to installing more cooling, it's running stock)
EDIT: Oh ya! My drivers are up to date.
Edited by monkeyfeet228, 22 February 2015 - 06:18 PM.