full computer reset? gas gauge stopped working?

today the entire computer "reset" including date/time + trip and continous trip mileage/time.
also, at the same time the gas gauge stopped working. and appeared on empty, although i knew there was at least a little gas in it.

coincidentally as i was resetting the time, i noticed that the gas gauge was giving a reading again - low on gas - but not empty.


Possible causes.
Noticed low on gas instantly after getting the car tinted.
Noticed computer reset two hours later (not continous driving) - could cold weather (28F) be an issue?

thanks!

have u recently killed or remove the battery

not to my knowledge however it sure does sound like it could be the issue with the date/time. Could the gas gauge (which now works) be at all related with a battery failure?


(i JUST put in a new battery in my '02 passat (B5) - i wonder if i can swap it with the old battery of the '02 audi . . .)