Help with bizarre booting problem

[surge]

So I have a really strange problem which I hope someone here can help with.
The system in my sig has been running fine for months but I have just started playing Doom which has completely crashed the PC when loading a checkpoint a few times (even running at stock CPU etc). Last time it happened, the BIOS came up with a message saying it had got corrupted and was loading the backup BIOS and would then not boot. So I flashed the BIOS (using Q flash) to the latest version and loaded optimised defaults. Now trying to boot from the OS (Win 7) just causes endless restarts, but it will boot in safe mode. But what is really odd is that it will not boot from the Windows DVD, just freezes at the windows screen after file loading. BUT, it will boot from the Windows DVD in safe mode.......No idea what this means- I have tried all the usual things (memtest etc, trying a different DVD drive, different SATA cable etc) to no avail
Any ideas?
Thanks

 

[surge]

I fixed in in the end-turned out to be nothing to do with the hardware (did the same on another board) but some UEFI Legacy conflict. Behavior was as described here

https://www.youtube.com/watch?v=LkY7Zu9B6JY

Mind you it took several goes of clearing CMOS and setting everything to legacy before it would work.

Posted this in case it helps somebody else