f2 and f12 are the only options given.
f8 does not work(tried repeat tapping/holding)
Press F5 at boot and pick boot in safe mode with a command prompt. Then run the program bootrec.exe from the prompt. Instructions on that program here http://support.microsoft.com/kb/927392
There is a decent chance you will not be able to boot to the command prompt at all and need a bootable Vista disk.
I assume F2 gets you into the Bios, what does F12 get you? Don’t let it change anything until you know what it’s changing.
Did it come with Vista? If so, did it come with an O/S disk or is it on a partition on the hard drive and you were supposed to burn it onto CDs or a DVD?
My Sony laptop had Vista as well on a separate partition you were supposed to burn your own copy but I seem to recall there’s a way to boot into that.
Have you backed up your data? If you go through a restore using Toshiba’s utilities, assuming it has them, it’s possible it will format your disk losing all your data.