Today my PC randomly froze up while I was browsing the internet. Just before this happened, I heard one of hard drives revving up (not abnormal behavior), and then a sudden blast of white noise from my speakers for about 1 second. That's when I noticed the cursor wasn't responding to my mouse. I tried to power it down, and it did not immediately respond...but eventually it did and booted up OK. Then it happened again.
This time, when I tried to turn it on, the HD access LED and the fans in the front (and their LEDs) repeatedly powered on and off every few seconds. Eventually it stabilized and booted up. But it still would freeze up and shut down without warning.
I took it outside and blew out a year's worth of dust, thinking it was maybe an overheating problem, but no. Still having issues. I'm actually surprised it's stayed up for the last half hour.
CPU: Intel i5-750 @ 2.67 GHz
Motherboard: Gigabyte Z68XP-UD3P
PSU: Corsair HX520W
Memory: 4 GB
Video card: AMD Radeon 5850
Running Windows 7
I'm suspecting it's the power supply. Most of the components are almost 5 years old at this point, but a few are a little newer than that. It's all been running pretty well for the most part. If anyone has any suggestions, though, I'd appreciate it.