Boot folder and bootmgr file are in the Win7 drive, OK, thats good.
That large partition has Ubuntu 9.04, forgot to mention it.
...An hour or more later...
I solved my problem, I'm on Win7, I've got GRUB installed, almost everything OK.
Now, I was looking around GRUB, and to boot, it is required to tell GRUB where (HD and partition) the OS is hosted on.
The 500GB HD is hd0 and the 80GB is hd1. My Win7 installation is installed on a partition at the 500GB drive, but in GRUB, my Win7 option is hd1, 0 (80GB drive partition 0), and THATS weird, because W7 isn't installed on hd1, but on hd0, and I need to have the 80GB drive connected to boot Win7...
Strange, but true.
Anyway to change that? And HOW did that happen? I'm really confused.