You can use BIOS Agent to check your BIOS version, among other things. One source of download is -
*www.majorgeeks.com/The_BIOS_Agent_d5038.html
It's also available through softpedia -
www.softpedia.com/get/System/System-Info/BIOS-Agent.shtml
The simplified version number is also often given near the top of the POST screen when you turn on your computer, e.g. 1.04