Do i have a virus on my Powerbook G4? PLEASE HELP

There are no viruses for OS X. There are only trojans but those you have to install and insert your admin's password.

the time and date change could point to a dying or dead pram battery
the networks problems could possibly be solved by a permission repair (that helped on my ibook when i just could not get the airport express card to connect to my router)
on the other hand some powerbooks had some problems like failing ram slots and some problems with the airport express failing , but that would be the worst case scenario depending which size screen ( because unlike in the iBooks apple did not consider to get the airport card fitted userfriendly in the PowerBooks )

Any time that's ever happened to my old macs it's the PRAM battery, most of the time those can be replaced via eBay for under $10.

PRAM battery. The problem connecting to the internet is a result of the fact your PRAM battery is dead...the computer actually thinks it's in 1969.

Unix time starts 00:00:00 January 1st 1970, with your timezone (UTC-X) that equals 31th December 1969.

But anyways, your PRAM (Parameter RAM, one of the parameters is the time) battery is dead.
You didn't state which kind of PowerBook G4 you have, so pick the guide to replace the battery yourself: Titanium or Aluminum.

MacHamster68 said:

that helped on my ibook when i just could not get the airport express card to connect to my router [...] problems with the airport express failing

Click to expand...

For clarity for those reading this later, this should be Airport Extreme, not Express. Express is an external mini-router that gets plugged into a wall, Extreme is the internal card.

I'm sure this was simply a mixup, so I wanted to clarify.