I'll be honest, you will be pretty much fighting a losing battle to get your usb's working if thats what's happened.
If you don't want to lose any of your data, remove your old HDD, get a new HDD and install Vista on it, using your existing product key.
***WARNING*** you are not allowed to reinstall a Microsoft O/S because of a change in motherboard, but you are allowed to in the case of a change in HDD. So all I'm saying is, if the installation asks you to phone up for activation, an automated voice may ask why you are reinstalling, never say motherboard always HDD failure
Then add your old HDD (as slave, or secondary IDE or SATA2,3 or what ever) when you've finished installing.
As for your BIOS, the usual keys are either DEL, F12, F10 or F2 (depending on the BIOS manufacturer) at boot up, then determine the boot priority from there