I need help !! ... keyboard cures for kernel panics(??) and other problems of unknown nature

Question

OK, let's just start with I'm an idiot !! I know very little and more than enough to be dangerous !!
The machine is a G4 QS 800 DP running Tiger 10.4.11, it had been working well until about 10 days / 2 weeks ago when problems started, about the same time the Firefox, 3.6.18 update came out and I installed it, the problems may have started BEFORE the FF update by a couple of hours, just not sure now.
I was surfing the net and was interrupted with frozen, darkened screen with a multi language message saying I needed to restart the computer, OK, did that, then about an hour later the same darker screen and message, Ok do it again, then again less than an hourlater again, then 45 mins., then 1/2 hr, then another 1/2 hr, then 20 mins., it continued like this for the next 5 to 7 hours, and 9 or 10 "crashes", all the time the same message, I never saw anything else on the screen for any kind of warning or kernel panic (don't know where they show up).
So the battery is 15 months old and tests good (bought a new one anyway, no change, same problems), did the PMU, several times, for sure wrong & to often, no help there, maybe one out of 100 times I could get it to stay on & get online for awhile by holding the command +S keys till the grey screen started, then release them, the rest of the time, it would begin to start up, 10 to15 seconds and die, ... getting very frustrated I tried the reset on the front, no change, then try the "programmers button" (I said I was dangerously smart) then combinations of PMU, reset, prog'mer buttons, Battery out PMU , battery in Pmu, everything disconnected each time, grounding myself each time, trying to not screw up, but knowing I must have many times, even tried a GOOD HDD that BDAqua checked & partitioned for me that is still blank (no OS yet) with install disc & holding C down, still no good action, for few try's I had both hdd's plugged in and got small icon's 1 & 2 for both hdd's while they were in & plugged in.
I talked with BDAqua on saturday, late, after hours, he had already waited for me, so as I described what I had done, HE said that the PMU should be held for 20 TO 25 seconds (or longer maybe in some cases, my impression of what I was hearing), and here is the BIG THING he said that gave me an idea to ask this question, BDAqua asked if I had / suggested I try, doing the PRAM RESET 5 TIMES IN A ROW, of course I had not, and haven't yet. I did do it a few times in all that I was trying, but never in a row, because 1 time never got a positive result, I  didb't think of multiple resets (I'm not all that smart, just dangerous). but from our talk, I think I understand it to mean, It may take many ( or multiples of 5 ?) to clear out (flush out the evil demons from the kernels ???) .......
SO MY QUESTION IS THIS; WHAT ARE THE MAGIC KEYBOARD STEPS / KEY COMBO'S, AND / OR PMU, OR RESET BUTTON, OR PROGRAMMER BUTTON SEQUENCES TO FOLLOW, BEFORE I GIVE UP AND CHANGE THE MOBO, CPU'S, OR WHATEVER, TO TRY AND SALVAGE MY G4 QS ???
ARE THERE MULTIPLES 5 (5, 10, 15, 20, 25 PMU RESETS TO CURE CERTAIN problems, like magic combinations ???)
....... any tricks of the trade that I can try, I have only had this machine for15 months and really like it and want cure it's troubles and WHAT EVER I DID TO IT THAT WAS WRONG !!!, it's a self esteem thing at this point, I can let it beat me because I hurt it, I must make it good to sve my own feelings, even though I did wrong, I must make ammends !!!  
Many Thanks To All That Take The Time To Read This, ...  And More Thanks to Those Who Help,  My Deepest Apprecaition To All,  ......  wayne146  .......

Answer 1

Trouble Shooting and related keyboard commands:
Startup Manager: How to select a startup volume
Mac OS X: Starting up in Safe Mode
Resetting your Mac's PRAM and NVRAM
"To continue booting, type 'mac-boot' and press return" Message
Resetting Cuda/PMU on Power Mac G5, Power Mac G4, Power Macintosh G3
Resolve startup issues and perform disk maintenance with Disk Utility and fsck
Mac OS X 10.4, 10.5: Gray screen appears during startup
Mac OS X 10.4 Help: I see a blank blue screen when I try to start up my computer
Avoid unnecessarily resetting the SMC or PMU for troubleshooting purposes
Note: There is NO magic time required to clear the PMU. A firm, complete push is all that is required.
The PMU reset button is a momentary contact switch because the reset only requires momentary contact.
Another myth is that more than 2 chimes during a PRAM reset resets better.
A reset is a reset.
If you need more than is done in a PRAM reset after 2 chimes, use the NVRAM reset in Open Firmware.
Keyboard Shortcuts:
Mac OS X keyboard shortcuts
Keyboard shortcuts - Mac Guides
Keyboard shortcuts in OS X | creativebits
Mac OS X Keyboard Commands
what does "DOS" mean ??  " boot in to DOS ", as you used it ??
Disk Operating System
That would be "DOS like" as in like the screen that you use in booting a Windows machine.
It's the black with white text screen that you get when you boot to Open Firmware (CMD+OPT+O+F)
Booting Mac OS X