Also...(you probably already tried this, but just in case)... with any receiver, the first thing to try is to unplug it for a couple minutes.
I've had older analog receivers that would get into all sorts of strange modes, but if I unplugged them for a while, everything would be OK. I also have a fairly new
HDTV, that got into a strange condition, where I'd hit a button on the remote, then I'd have to wait about 45 seconds for it to register on the TV. Made it impossible to key in a channel like 13. Ie it would go to channel 2 then 3. Unplugged the thing for a minute, and it's been fine since.
Another thing, I don't know if this is likely with a receiver, but some computers will slow down if they overheat, so you might check to see if it's generating more heat than normal.
One thing that many people over on the satforums forum complain about is cheap capacitors in consumer equipment, so it's also possible that the capacitors dried out. I had this happen in my Roku HD1000,which is a great gadget that you can stream video to from a PCI FTA card, but apparently they were produced with cheap capacitors, and when they would dry out, the Roku would keep rebooting over and over, and some other strange things. I sent the thing back, and got a refurbished machine back, which has been fine. So it's possible that the
Mercury may have a capacitor problem too. So if we start to see more problems of this type, it may indicate that Fortec skimped on the quality of components in the receiver.