Odd experience with an invalid system date

I'm in the process of restoring my system from a recent backup ... the reason for the restore is quite odd.

I was playing around with some GPS software ... and accidentally clicked an option in the software to set the system date to the GPS calculated date (GPS's depend on having highly accurate clocks).

The date that was set, however, was January 1st, 1899. Clearly the software has some problems.

Once the date was set, all hell broke loose ... software started cashing, Zone Alarm went into unregistered mode, Symantec AV crashed, and half a dozen system services crashed.

Even after I reset the date, the system wasn't right ... system services would still crash during startup.

I tried rolling the system back to a recent restore point ... but the restore software said it couldn't perform the restore (I tried several restore points).

I'm quite perplexed as to why this is happening ... I just hope that restoring to my 3 day old backup will be sufficient. I really don't want to have to reinstall the system from scratch.

Anyone have an idea why the system date getting reset would cause so much chaos? I can understand ZA going into unregistered mode, but why would everything else crash? And why would it things continue to crash after the date is reset?

david