Brian -
As long as you don't have any other RS-232 devices on your Vista box, that should EXACTLYwork.
Be mindful... flashing your firmware is the LEAST of the things you can do with this interface; pretty much all your MFCs use the USBasp or similar adapter to actually configure the controller, and many of the GUIs that have been devised for popular controllers are way more powerful than the menus in the KK2.0.
The KK2.0 doesn't even NEED the LCD; it's just there to help people overcome the initial
"AAAAAAAAAAH!!! SERIALCOMMUNICATION!!!FLASHINGFIRMWARE!!!ARMAGEDDD ON!!!" heebie-jeebies. Once you see what you can do with the USBasp interface, you'll probably only use the LCD to do occasional tweaks in the field anyways. Of course, it can be taken off; fortunately, HK made that part easy.
And my solution to the flopsy LCD was horribly low-tech, I'm afraid; after finding that the only thing actually holding the whole LCD and backlight thing ON the board was 2 solder joints and a strip of servo tape, getting crazy with making brackets seemed absurd, so I just hot-glued the tarhooties out of it. I found I had to run a careful bead across the entire top there where the black stripe is; that is silicone, so the hot glues wasn't interested in sticking. That, plus a thin strip across the top edge, and a gob on each of the feet on the backlight right at the PCB. When you see yours, you'll understand.
mnem
Are you serial?