You can check here: http://www.adobe.com/products/flash/about/ to see which version you should install for your Mac and OS. Note that version 10,1,102,64 is the last version available to PPC Mac users*. The latest version,10.3.183.23 or later, is for Intel Macs only running Tiger or Leopard, as Adobe no longer support the PPC platform. Version 11.4.402.265 or later is for Snow Leopard onwards.
* Unhelpfully, if you want the last version for PPC (G4 or G5) Macs, you need to go here: http://kb2.adobe.com/cps/142/tn_14266.html and scroll down to 'Archived Versions/Older Archives'. Flash Player 10.1.102.64 is the one you download. More information here: http://kb2.adobe.com/cps/838/cpsid_83808.html
You should first uninstall any previous version of Flash Player, using the uninstaller from here (make sure you use the correct one!):
and also that you follow the instructions closely, such as closing ALL applications first before installing. You must also carry out a permission repair after installing anything from Adobe.
(If you are running a PPC Mac with Flash Player 10.1.102.64 and are having problems with watching videos on FaceBook or other sites, try the following solution which fools the site into thinking that you are running the version 11.5.502.55:)
Download this http://scriptogr.am/nordkril/post/adobe-flash-11.5-for-powerpc to your desktop, unzip it, and replace the current Flash Player plug-in which is in your main/Library/Internet Plug-Ins folder, (not the user Library). Save the old one just in case this one doesn't work.
Yeah, I already saw this exact same reply that you gave to HT1338 Why Can't I install Adobe FlashPlayer on my iBook G4 OS 10.5.8? Way too much information that is not specific to this machine. If I had found your reply to that guy helpful I wouldn't have wasted my time posting. You see, I don't know what I have beyond the rudimentary bits of information I originally provided.
See, I'm also trying to determine if this machine deserves anything beyond relegation to a landfill. Someone told me that there's a near correspondence between the capabilities of this laptop and a Windows PC running Windows 98. If that is indeed the case, tell me, and I'll waste no more time of mine, or yours.
My son wants to use this for music. At school he's used a PC to go to a karaoke site, one where you can pay a fee and download individual songs, and you then have the ability to remove vocals or bass or drums or guitar, or any combination. You also can preview the track before to buy it.
I would suggest you buy him a similar computer, rather than the old and officially obsolete PPC G4 Mac that, apart from the method I explained, cannot be updated further.