Not sure if that's a typo but you hold down B when you turn it on or hit the reset button, not when connecting. When you boot the Dingoo while holding B it will actually appear to be off - the screen remains off - but it forces the CPU into a boot mode. Then when you plug it in, Windows should see it as new hardware and when it asks for drivers, point it to the driver that came with the flasher tool.
I tried a few GBA commercial roms this morning and found a much lower ratio than I expected - very quick test but out of 3 that I tried, only 1 appeared to work properly. Maybe it's flawed and I just didn't notice as I really just play GBA homebrews.
I've been reading the forums at dingoonity.com but I don't recall seeing anything about problems there, I'll check again though, and try testing the rest of my GBA roms tonight.
Cheers!
p.s. It should be 'game' on the Dingoo, not 'games'... if the original 'game' folder is there and you've copied the 'games' folder in addition, The dingoo would be running the original emus not the hk-fix ones. Just mentioning that just in case.