While I have yet to have a bad motherboard myself. If it was confirmed the motherboard was dead in one of my brainboxes. It's usually harder to find just the motherboard. And sellers frequently charge almost as much for just a motherboard than a complete, tested replacement 660 brainbox.
It's also a lot of time and effort to remove/reattach all the other components that are in the way just to be able to remove/reinstall a motherboard. Also, it can be easy to miss "something" when installing it. Or accidentally break something else in the process or overlook something so it doesn't boot when done. That would drive me nuts if I took all that time to remove and replace the motherboard in a brainbox.
I'd just get an entire replacement 660 brainbox that's complete and tested, has a working 80GB IGT SSD with the OEM SSD holder, and since they don't have on-board video, they all have the E4690 PCIe video card in them from GET-T for $150. Just doesn't have bios chips which I'd replace anyway.
https://get-t.net/product/cpu168/When I bought a few additional AVP's over time. If I got one which didn't already have the E4690 video card in it. I would get one of these from GET-T, replace the IGT 80GB SSD it comes with. But with SSD's and RAM like 4-5 times as expensive these days (which is also crazy!). The exact SSD's I paid $15 for last year are now $65! And a pack of two, name brand 32GB DIMMs for 64GB total of very fast memory that I paid $45 for last year. Now that memory with the same exact part number costs over $250! Insane! I never used them and they're still sealed in the package... I should sell the unopened RAM for a profit.
So that can save some money too as the IGT SSDs work fine, and 80GB is plenty for most setups. Plus, there is no guarantee that it will, but 95% of the ones I’ve bought had 4GB of RAM even though it's listed they only come with 2GB. I believe in the 660's that IGT shipped or were already in a machine had 4GB of RAM in them by default.
And they really don't want to do a lot of work with brainboxes at GET-T when they get say a pallet of them or tear down machines with 660's in them for recycling. Instead of going through and removing parts to resell them. They just blow it out with compressed air, power on test it with a diag key, remove the bios chips and ship it out. Both the main and CPU fans are usually good too. I've bought many of them, and half the time one or both of the bios chips were still in it! They also really pack brainboxes really well for shipping! I’ve never received a bad one from them and they were packaged so well that none have ever been damaged in shipping.
Then you have a good working brainbox again with really no effort. Huge plus if your brainbox with a dead/damaged motherboard only had on-board video without the E4690 PCIe video card. So I'd totally go with a complete/tested 660 brainbox than replace a motherboard. If your power cable is for the older model brainboxes with the USB power supply box mounted on the top of the main brainbox, fairly easy to source the single power cable used on brainboxes like the 660 that have that USB power supply "inside" the main brainbox. Since you also get at least one extra 2GB RAM stick, usually two, an IGT SSD, and an E4690 PCIe video card included and just put that in your machine instead. Or if you only have one brainbox, for the price it’s good to have one as a spare. And just put the box with the bad motherboard on a shelf for any parts that may still be useful from it.
Why GET-T sells complete complete/tested brainboxes for $150 that have the video card already installed in them. Yet they also sell the video card all by itself for $150 on their site I have no idea. But no complaints here. The few E4690 video cards for sale on places like eBay, the sellers are asking like $250 for just the video card.
Only reason for all this babble is I ordered another one from GET-T last week since they’re inexpensive, and I have 5 AVP’s so a brainbox on one of them will likely puke out at some point. And they increased the price to $200 about 6 months ago, but they dropped it back to $150 recently. No bios chips in it, but it did have 4GB of RAM installed. Very clean, with good fans.
Installed the bios chips, put in new batteries. Plugged it in and did a wipe and clean install with just a few random games installed to test.
And when it was all set up, I exited, closed up the machine. And to my surprise. It displayed the same “Game Theme License Tilt – Selected game theme is not licensed” that you experienced! This was a first on any of my machines.
But after about 10 seconds the tilt disappeared. Never saw it again and everything worked just fine. Put it on the shelf so now I have a spare all loaded up and tested. My guess is it just came up because it was a total wipe and load of the machine and it was the first time it was in normal play mode with everything closed up, but who knows. Still doesn’t explain why this would come up for anyone and not clear by itself. But eh, eeproms “can” go bad. It’s just really uncommon if it was flashed good originally.
Glad you found the problem and it wasn't a big hassle to fix!