I had a similar problem recently with my Dynamis.
I came back from a fortnights holiday abroad to find that my Dynamis Controller wouldn't operate any locos at all, despite it having worked perfectly for 18 months or more.
I have more than one handset (there are more than 40 locos on the layout & I don't want to spend time re-entering data), and none of the handsets would operate a loco.
The symptom I had was that the light on the infra red receiver flickered green rapidly when switched on, and didn't settle down to a static green display as normal.
On a hunch, I borrowed another Dynamis set from a mate who lives 2 miles away. I wired this one into my layout and guess what........it didn't work either, but showed exactly the same symptons. I then took MY OWN Dynamis to his house........and it worked!!!
Thus I knew at this point that the fault was the location where it was being used, not the equipment itself.
The next step I took (a bit desperate I know!) was to phone Western Power who supply our electricity. They turned up very promptly, and the guy, like me, assumed that there was maybe a voltage drop to our property, or even a dirty supply. Much to my disappointment his readings were normal, so I was almost back to square one.
Next, I decided to unplug appliances from their sockets - fridge, TV, lights, clocks, switched off central heating etc etc - to no avail.
However the following day, continuing on this theme, I found the culprit.
I had kept the Dynamis switched on as each appliance was disconnected and as soon as I switched off the PC, the green receiver light on the Dynamis steadied.
I tested it and found it worked perfectly.
I should point out that the PC doesen't operate from the same room as the model railway.
Further investigation though, showed that it was NOT the computer that was affecting the infra-red, but the Belkin WIRELESS ROUTER we were using.
This has now been permanently disconnected and the Dynamis is back to working fine.
The only unsolved part of the puzzle is - why did the Dynamis work fine for 18 months, then suddenly become susceptible to the router.
Anyway, I hope this helps.
Best Regards
Steve