Ok I've got both OS Running (Pulled my Vista Drive when Installing 7) on two drives. Right now I switch via the BIOS (Selecting what Drive to boot from) I've also got Vista set to Not "see" the 7 Drive (Doesn't map it) And Same for 7 (Doesn't map the Vista Drive) Now is there a way to have one drive bring up the Load OS so I can choose between 7 / Vista / Ubuntu (Installed on 3rd drive) Or should I just stick with using the BIOS (F12) to select my OS?
Windows 7 (and Vista) install a boot manager that will allow you select the O/S at start up. Microsoft didn't suppy a nice GUI interface to configure it, but there are free applications available to make it easy to do what you want. I've been using EasyBCD to configure it. I'm able to select between Windows 7 and Windows XP.
Actually you can configure it from within OS: Control Panel\System and Security\System\Advanced System Settings\Startup And Recovery I use VistaBootPro 3.3
I used EasyBCD and it works perfectly, easy to use. what @tomorrow said is not all true, as if you installed each OS on a different disk (while the other HD was disconnected), windows will not see both OS's in that menu, first use EasyBCD to add vista to the Win7 bootloader (as vista bootloader doesn't understand widnows 7 booting method), then leave bios to boot from win7 disk, you will have the boot to select which os to start.
You can select the default O/S and the timeout from here once you've got all your O/S's added to boot manager, but you can't add them from here. So to get your additional O/S's into boot manager in the first place, you have to either deal with its command line interface or a GUI frontend like EasyBCD.
but in my case it is. I have vista installed since 3 years, i got a new HD and installed win7 t o the new hd, but the installer updated the bootloader of the vista hd as it is detected as primary HD, now i have to reinstall with vista disk disconnected so that win7 puts its bootmgr on the new hd...