I can't help with first hand experience because my pcs are both now W10.64. I had an old generic bluetooth adapter which I don't normally use, but just plugged it in and it has happily connected to a 'phone - so there's nothing wrong in W10, and I don't really see why 7 would be substantially different.
Have you only just started trying the bt devices or did they ever work properly (except for yesterday)? Are you using Belkin's driver or Microsoft's; and have you tried deleting one or the other and trying again? I'd guess that you have..
Have you tried plugging the adapters in through a usb hub? I have a couple of MS keyboard/mouse sets that won't work properly with the transceiver plugged directly to the pc, but are fine when in a hub.