Imac help with booting into windows only

Well lets see where do we start. So I have a 2006 I mac (g5) i think of what it's called. it does have a plastic case and there is no glass on the screen. I called Apple and they were very kind and sent me a copy (for free) OS X 10.5.6. The machine is a Intel core machine. I cannot get into the OS of the machine it will only boot up into Windows XP Pro. The machine is Username and password protected of which my brother can't remember UGH!

The machine will bong upon start up and boot to Windows as normally. What I have noticed is that the Apple mouse and keyboard won't start working till AFTER windows has gotten to the username and password.

What have I done so far:
booting up and holding option key
booting up and holding option key pressing c
booting up and holding option key pressing s
I have tried resetting the PRAM
I have tried resetting the PMU by holding the power button and plugging in the unit
All of these things have been tried with the Apple Disc in the drive.
I have called Apple but they would like several hundred to "fix" it This computer was free given to me. I have no idea if everything works why would I spend ton of cash on a unit if I don't know if it's 100%

The only thing I know the USB bus does not boot till after windows does. I don't know what else to try so please HELP!

First what happens when you hold Option. Remember, right after the Startup Sound you HOLD down Option and KEEP it down. Does a boot menu come up?

Second, With the OSX DVD that Apple sent you in the drive, right after the Startup sound, hold C. Not Option C, just C. Keep that does. Does OSX start to boot from the DVD?

What usb keyboard are you using? Apple or some other brand?

Dennis thank you so very much for your quick reply I did just try when I got your reply holding the option key all the till I got to the Windows screen and did not let go and I got no Apple boot screen. I also did try the holding the C till the windows logging come on, with no change The keyboard is a wired Apple unit and the wired mouse plugs into the keyboard

When the computer boots the Drive will spin but no other Apple menu's or boot options show on the screen. Thanks for your help I hope this is hopeful information.

Just curious, what apple keyboard? Is it white plastic or Aluminum (Metal)? There are SOME Macs that the Aluminum keyboard keys will not work till you are in the OS. Your iMac should though.

It sounds like you have the first generation Intel iMac. A G5 is a Power PC CPU so it's not that.

Let us know on the keyboard. Do you by chance have a USB PC keyboard you can try?

It's a metal keyboard and the CPU and screen are all in one. This not the round ball base unit.

Do you have another USB keyboard you can try? I have a metal apple board here and half the keys do not work so it could be the keyboard. It can be a PC keyboard.

Let me take a look if I do It would be a non Apple one but, if it works who cares Lemmie look!

Nope all the Keyboards i have are the S type connector BOOOOOOO!

I was able to get a windows keyboard and HA....IT'S ALIVE!!!!! Hot dang!

GREAT to hear that. Something might be wrong with that Apple KB. Once in OSX plug it in and try all the keys. Just curious as some of the newer metal ones only work at the startup on some very new Macs. Very poor decision on Apples part though.

Yea everything on the metal keyboard is working just GREAT!!!!! I have been able to update all the software but the version of OS is 10.5.8. How can I upgrade to newer versions? I have my crazy I tunes from my PC moving into the Imac now man what a trip! the model identifier is 4,1. What other info would you need from me. This is exciting I do have to tell you!

OS X.5.8 is the final operating system for PowerPC computers, which is what a G5 is. Think the model 4.1 is incorrect as that is for a 2001 G3 iMac. You do seem a little unsure, so when booted from leopard click on the Apple in the Menu Bar and then About this Mac. Under Processor will be your computer details. if it is an Intel Core Duo you can purchase Snow Leopard from Apple online for $29.00.

If it happens to be a Core 2 Duo that will run Lion, the latest operating system. You can download Lion from the App Store if you are running OS X.6.8, another $29.00