Someone just gave me a Poly800 and when I turn it on I get "SAVE" on the dispaly and no sounds is coming out from the keyboard!!!
How can I do a factory reset or is there another way to get the keyboard to full normal fuction???

Call up korg.com and ask about the reset process for the Poly. Its been so long, I can't recall it, but virtually all synths can be reset by holding down certain buttons and/or stepping through a couple of specific presses upon power-up.
It might even be quicker to ask a local shop that sells Korg gear. When I sold synths, we had a file cabinet of old manuals, etc. containing just such "arcane" details waiting for someone in your position! Give it a try.
If that doesn't fix it, uh....break out your checkbook! Repair time!

P.S. Forgot this part! If you have a data cassette for the Poly and you can get it to the "load" stage, try dumping a full set of sound data into it. That may cause it to snap back.
If you don't have such a cassette, you might be able to get one from a sympathetic person at Korg proper or you can buy one of several from kidnepro.com.

Wait a sec, before you try anything else check the back panel. One of the 3 slide switches on the back is marked TAPE:Enable/Disable. Make sure this switch is on Disable otherwise I think all you can do is tape operations. Hope this is all you need to do!mn