Suunto Vyper - help!

[demisvmax]

Yesterday, just before I start descending and diving, I noticed my Vyper was switched off. I tried to switch it on but since I am using my Citizen Cyber Aqualand Nx watch as reserve I decided to continue the dive. When I checked it again at about 4m it seemed to be working properly and Ι observed it cautiously during the whole dive. I thought to be something XXXX with electronics.
Today, I decided to download the dive profile and I noticed that the date on the Vyper is 01/01/00 and time 18:00! Also at some point it showed TEST 25. I tried to set the time and date correctly but after a while it was back to 01/01/00 and 18:00!!
Is it dying? Already dead? Unreliable?
Any suggestions?
There are no warranty issues since I bought sometime ago secondhand from a friend.
Any help appreciated. Thanks!

[navyhmc]

Sounds like it may be a dead battery. At least that's my first guess. That or there's a bad connection somewhere. Another thing could be a small unnoticed flooding.

[demisvmax]

I changed the battery myself and it was the fifth dive since then. But I must say that before I started using it when I got it, I gave it to a friend to dive with it and he brought it back flooded from the battery compartment. I opened it, cleaned it, installed new battery and was working fine until yesterday.
You think that the previous flood affected it and maybe it started to show signs just now? Can this be possible?