I've been having some problems with my PC as of late and I'm at a loss as to what the problem could be
Here's my specs, just to get it out of the way.
MB: Intel D915GAG
CPU: Intel Pentium 4 3.20 GHz
GPU: Nvidia GeForce 9400 GT
OS: Windows 7 Home Premium
RAM: 3 sticks. (1x1GB, 2x512MB)
Caseflow: Antec 300, with all fans installed.
It all started about a week ago. The monitor would display "No Signal" and I'd notice that my keyboard light would shut off. The fans would all still be spinning, though, just no signs of life otherwise. I'd have to do a hard shut down.
This happened even in Safe Mode. It just seemed to be randomly. Sometimes I'd be browsing the web for 30 minutes and it'd happen, or it would be two minutes after boot. Really random.
I reseated everything other than the heatsink. This includes RAM and my GPU. I also gave the PC a really good cleaning of dust, including all fans and components.
Eventually, I ran a system restore from within Windows Restore on boot. Everything seemed to have fixed itself before this morning, when it started acting up again.
The PC froze at the boot screen, then upon hard reboot, it froze at the Windows loading screen. Finally, I was able to log in and the PC just locked up after about 5 minutes. I had to restart. It'll also occasionally just reboot itself, even though I have automatic reboot turned off in advanced settings.
Here are the things I've done so far:
Remove GPU - I took out the GPU and hooked the monitor up to the onboard graphics. Same problem, I lost signal to the monitor and had to reboot.
Ran MEMTest+86 - Everything came back good.
Ran Intel's Processor Diagnostic Tool - Everything passed.
Removed, cleaned and repasted Heatsink. - Added new thermal paste and made sure the heatsink was clear of dust.
Ran Anti-Virus - I've run Avast with a full scan as well as Malware Bytes and both came back clean.
I'm really out of ideas here. The PSU I have is about 9 months old. Never had any problems with it. It's 585W. I didn't have any issues with the old one I replaced this one with, I just replaced it to be on the safe side as my old one was getting pretty old.
I've had this PC for about 6 years now. The MB and CPU are still from the Gateway 506GR I bought way back when, as is the two 512MB sticks of RAM. Everything else I added myself over time.
The ONLY thing I added THIS YEAR is a second HDD. A Seagate 2TB SATA for extra storage. I installed that drive a few months ago.
I've also been monitoring Speedfan, and nothing seems to be running too crazy hot. My CPU and GPU both idle at around 60c give or take. I can't seem to get those temps any lower, though, and I've heard that my individual CPU was known for running on the warm side anyway.
These issues seem to have come out of nowhere and I'm really at a loss to explain what the problem is. I'm hoping you guys can give me some ideas or insight. I'm hoping that it's not my motherboard beginning to go, but we'll see. I know my MB and CPU are getting up there in age but I'd rather not go out and buy new (because if I start with a MB and CPU new, I'll just end up building a whole new PC) if I don't have to.
Thanks in advance.