Macbook Air clock is set before March 31, 2001

Question

So, I just purchased a MBA for a client of ours. I made sure the battery was charged fully as I was setting up the machine, and upon handover instructed them to drain the battery and force the machine to sleep to condition the battery on it's first cycle. They performed this and charged it up fully again.
They let it fully drain again (unintentionally), and plugged it in put didn't turn the plug on, so when I arrived at it the following morning, it had no battery. I gave it some power and woke it up (it restored from it's previous state) and was then welcomed with your computers clock is set before March 31, 2001 error.
Any ideas what the problem could be? Since this I've noticed it wont remember their wireless network password etc? I'm guessing this is a PRAM issue, and perhaps the PRAM button battery?! However, this machine's a couple of days old?
Any thoughts much appreciated.
Oli

Answer 1

While I'm unsure why March 31, 2001 was selected I am curious...
If your reset the SMC/PRAM and set the clock correctly does it continue hold the correct date/time settings on reboot? If you were to drain the battery again, does it hold the settings?
Another user touched on the keychain issue for the WiFi network password, so you'd want to check their first. I've also seen issues with WEP-based encrypted networks requiring a password on reconnect even when stored in a keychain. Whereas on the same machine a WPA2-based encrypted network does not! (Unsure if there's some sort of keepalives feature of WPA2 that WEP lacks).
As far as the PRAM goes, I've only done a full disassembly of the MBA once and the battery was certainly not obvious. If you look at the MLB photos that iFixit.com took during their disassembly you can see for yourself what the innards look like:
http://www.ifixit.com/Parts/stream/9/thumb/17-2.jpg
http://www.ifixit.com/Parts/stream/9/thumb/18-2.jpg