Yes, you may have it installed already, if not you will probably have to go to Adobe's web site to find the older software as I don't think it's being updated anymore for 10.4.
I have a Apple ibook G4 10.5.8 and don't know what flash player to download
Yes, you can.
No, but you can use Office Mac 2011. To download a trial version, see the related link.
Sims 3 will not work with a G4 iMac. The game requires a recent Mac with an Intel processor.
If a G4 iMac is working but starting up without the chime it may have been shutdown with the sound muted or there may be headphones plugged in. If it is not starting up at all then it will need repairing.
I think the oldest imac I recommend is the iMac g4 (only if it's running tiger) you could purchase one on eBay for about £65
The iMac G4 is able to run any version of Mac OS X up to and including, version 10.5 (Leopard).
The original iMac was the G3 which came out in (1998). It was followed by the G4 (2002), then the G5 (2004), then the Intel iMac plastic version (2006). The 5th iMac was the aluminum iMac which came out in (August 2007), followed by the iMac Aluminum Unibody (2009). The newest iMac is simply called 2012 iMac and it came out on November 30, 2012.
Early ones has Mac OS9 and later ones came with OSx.
The G4 iMacs, with the screen on the swivelling arm, were a stand alone computer with all its workings in the domed base. It does not need anything else to work.
The best way would probably be to get a hardware specialist to download the photos of the main drive of your iMac.
check all plugs,back left button to turn on/put to sleep.