Are no sure sign so let's dismiss that.
The test for if its the PSU is to either measure the output with a Volt Meter or just switch it with a new good PSU.
"it's taken two or three tries to get it to fully power up (the lights and fans would come on for a split second, then die)."
This happens under a few conditions with a GOOD PSU. Here they are for you to research on google.
1. BAD CAPS.
I don't write more since plenty written already.
2. An IDE cable off by row, pin, upside down or a dead hard disk.
To test this I unplug the IDE cables.
I think my PSU has died, but I want to be more sure so I'm looking for a second opinion.
This morning, I tried powering on my computer and nothing happened. No lights, no fans spinning... nothing. For a while now, whenever I have turned my computer on, it's taken two or three tries to get it to fully power up (the lights and fans would come on for a split second, then die). I'm thinking this was my PSU telling me it was kicking the bucket.
Anyway, I have replaced the power cable, tested all the connections, and there doesn't appear to be a power light on the mobo, indicating I believe that the mobo is not receiving power.
The one curious thing is that when my computer is plugged in, but the PSU is turned off, my power strip's "grounded" light turns on. When the PSU is turned on again, it goes off. What does that mean? I don't remember if the grounded light is supposed to be on or off.
Another thing is that whilst there is no power light on the mobo, there is light coming from two LEDs on my Ethernet port, suggesting to me that there is some power coming from somewhere.
If anyone can help me confirm it's the PSU, I'd really appreciate it, or for any other ideas. Thanks.