Hi and Welcome!
Have you checked if there is a newer Bios available? Also: if there is, are there any issues with your computer that can be resolved with that Bios update? Just to double check.
The update procedure itself is described on HP website. If I remember correctly, then there are even tools that prepare an USB flash drive (should be empty before), so you are independent from the OS that is currently installed.
If you really want to run the Bios update in a Windows environment, make sure you follow the instructions given on HP website. There shouldn't be a difference if you are running Vista or 7 (even Win8 shouldn't matter), most likely you will have use "run as Administrator" option (Right-Click on the executable).