G4 quciksliver making weird noise, please help!

I have a G4 Quciksliver 800 mhz and when I press the start button it makes a high pitch noise/tone before the start buttons starts flashing quickly about 6 or 7 times, the G4 then proceeds to hang for about 15 seconds before it starts up. My Apple Studio Display start button also flashes at the same time as the G4 which I found to be strange.

Currently the G4 is booting up but this problem is occurring more and more and I am worried it is going to die on me and as I work from home this would be a major problem that I can not afford to happen at this moment in time.

I suppose I am looking to get some advice of what this problem is so that I can resolve the issue before it gets too late and the machine dies on me, if I can!

Someone had mentioned that it may be the battery that is needing replaced, can anyone confirm if they feel this an avenue worth exploring or if the problem is remotely connected?

Also any other advice/help is greatly appreciated?