Ok that's good, just wanted to be sure of how far you get.
So you can get to the EZ Flash 2 feature in the bios?
I think an attempt at bios upgrade is about your only alternative left apart from trying a different mobo.
Try going into EZFlash 2 and become familiar with how it works.
If the system still freezes after a couple of minutes that might still be enough time to try an upgrade.
When you are sure of what needs to be done, download the new bios file to a flash drive.
Pressing <ALT> + <F2> instead of <delete> will save you time and send you straight to the utility when you are ready to do it.
What is the bios version currently?
Do you have the motherboard setup CD?