I've had a PK5-E WiFi mainboard with a Q6600 CPU and an ATI Radeon 3870 for a few years now. The power source is a TACENS RADIX II 420. OS: W7-64.
The last few months, the computer has been behaving weirdly, but only when told to suspend, such as shutting off completely, not coming back up and having to flip the power switch to reboot or showing a pixelated login screen. The BIOS is the newest one (1305) and I've been blaming it on video driver and windows updates.
All of this time it has managed 3 hard drives and a CD-Drive perfectly, also behaving flawlessly during games such as Skyrim.
The only thing that has made me suspect the PSU is that after disconnecting the PC from the mains and reconnecting again, the power button will be unresponsive for half a minute or so. Also I have an internal card reader with a pilot led (it goes to the internal USB ports) and when connected after being disconnected it shines, then fades and then shines again.
I've tested the voltages: The BIOS shows them normal. HWMonitor shows a 10V average in the 12V rails, but the rest as normal. AIDA64 shows all voltages within 5% of normal.
I would appreciate any advice of whether the symptoms are related to the PSU or if they may be related to something else.