B3 crashes at least once a day

[wikan]

Hi Forum from Patagonia,
I am using my B3(no WiFi) since 3 years 24/7 to support an e-Mail system working over an HF- radio link. It was working like a charm from the time I got it out of the box and installed it (Server only) behind my router. Just using the three services to have fetchmail, dovecot, postfix and horde working. All sweet. Beginning of february, I had strange hangs once or twice a day, I could not ssh into the B3 and also the WebGUI was not accessible. Power down button did not work, so I had to pull the plug ( checking there was no light from my Corsair 64GB SSD on in the kensington lock opening). When reconnecting, I could switch the B3 on again -sometimes it would do so itself without using the Power button, sometimes I had to press the button.
Checked the logs ( system, mail, samba) but could not find anything suspicious. THe B3 sometimes would work 1-3 days in the beginning,, without probs. Then, over the course of february and now march, it needs to be hard-resetted at least once a day, mostly twice. One always has to toggle the three services in Email on and off, so it would fetch again and also let you access horde.
I was reading the forum to find some hint, tought of the power supply and put in a 12V stabilizer from TEN, also changed the ehternet cable to the router - to no avail. THe system log sometimes shows a message like: oops, we are 3 second behind in time...or other times there were some crashed horde mysql tables, but I checked and it seemed to be ok.
I re-installed the sytem partition with the USB stick, did try it with the latest image available on excito.com. First without system update, crash occurred again, then second time with system update, again I could not call it a victory, the system crashes again. Today, I will try to get a new battery for the board, but I reckon this is not the problem.
Now, and before I try to do a fresh re-install with the format=1 and partition=1, deleting all the user data (well I have them backed up), maybe you have an idea what this strange behavior of my B3 could be.
Waiting out for your suggestions,
w

[Ubi]

so it crashes but then you are still able to access the web interface. THat doesnt really make sense to me. And if it is a software bloack, why would the reason be that the power supply is faulty? Your post title suggests your machine resets once a day, but the tesxt suggests you reset the machine manually. Too much vagueness to respond to for me, sorry...
please start with your definiion of "crash", as it seems to be different what most people think it is.

Also, please do not put the same question in two fora