Hello and thank you for your question. I'm sorry to hear that yo are having trouble with the PA800.
I will need a little more information in order to help you sort this out.
1. When you say you formatted it, did you load the "Pa800_Format.pkg" file or did you do a NAND format from the service menu?
2. Exactly what is actually happening now when you try to load the operating system? Does the PA800 give any error messages?
OK, since we seem to have missed each other I've written up the steps for reloading the system, along with some notes about the most common things that go wrong. Hopefully that will get you back up and running, but if it doesn't, knowing where you are getting hung up will give us a starting point to troubleshooting this further.
Go through these steps. If they solve the issue then please rate me positively. If they don't solve it, then please hold off on rating and post a response detailing where you are running into a problem. Please be as descriptive as possible.
I hope I have satisfactorily answered your question. Please let me know if you need any more information.