system hanging before windows boots, unless...

I have a really strange problem that I've managed to narrow down fairly specifically. I pray someone here might have a good idea. Basically, I bought a new Gateway system, and made some changes. I decided to put in an additional hard disk, connected directly to the MOBO and install Win7 ultimate on that one, allowing me to preserve the win7 home that came installed on the supplied drive. I went into BIOS and made the correct tweaks I believe, but I'm left with a hanging system after it boots up.

I've narrowed it down to this: if I press [DEL] to go into BIOS and [save and exit], the machine boots and then where the machine normally hangs, it follows with an opportunity to [Ctr-P] to get into the Intel Management Engine BIOS, and then boots to Windows as it should. So it hangs in between those BIOS's unless I first [save and exit] the first BIOS.

Obviously Gateway's tech support is less than worthless, especially since I committed the cardinal sin of deigning to make changes to the system.

Thanks to anyone taking the time to read this and ping their brain cells for solutions!
-John