Power Mac G4 ac power cord question

Hi folks, I am new here and this is my first post, because I couldn't seem to find an answer to my question by searching on here. I have a Power Mac G4 AGP 1.25ghz x2 CPU and last night it wouldn't start up for me. When I went to hit the button to turn it on, it wouldn't light up at all. I then unplugged it and plugged it back in and the power button would light up but still wouldn't turn on.

I then read some posts here and reset the PMU, it then started up after that, but then after shutting down, it would not start back up again. I then unplugged the power cord and plugged it back in and it powers back up fine. So my question is do I need to replace the power cord? Also if I do, do I have to buy a specific one made by apple or can I buy a OEM one?

Thanks.

Bang!
The exact same issue with my G4 (MirrorDrive doors/FW800). I realized this yesterday. I hadn't used it for a while when I tried to boot it up last night. Pressed the button, no startup. Played around and finally disconnected it, reconnected it and started fine with the dong! sound and everything fine in terms of data , performance, etc.

I have the original power cable. Does the same with another power cord though. Turning it off and (very) quickly restarting it pressing the button would work. But when off for a few minutes, hours (or days?) I sure have to disconnect (or turn off the powerbar) and reconnect before it boots up again.

It's not a big deal, just a bit annoying, especially if this symptoms mean deeper troubles to come?!?! Could it be something like the lithium battery getting low? Probably my next troubleshooting move on this.

Any idea?

I'm pretty ignorant so I wouldn't trust my opinion but I wonder if it could be the little battery inside your hard drive needs changing. Just a thought.