This is sort of "Out There", and maybe I don't fully understand the condition, but make sure your hot water heater is turned off from the 110V setting as well as your air conditioner and inverter. It is good practice to have everything turned off before starting your generator. Once the generator has been running and powering the microwave display, wait 30 seconds more and then one by one turn on what you need. Just maybe too much is turned pre-on and the generator cannot initially supply the required power all at once.
It takes many seconds before the power transfer switch activates, causing the timed delay.
One other thing is the reset switch on the generator itself. If the generator gets over-loaded, the reset switch pops and needs resetting.
Again, I am sorry for not understand the workings of a current-day PC, but my suggestions should apply across the board....just not sure any of it will apply to the banshee74's situation.