Monitor sometimes not recognised by bios

[id_wright]

Hi there,
Not sure if this should be in this forum or under monitors, so apologies if in the wrong place.
Had an issue with bios sometimes not recognising my monitor (24" flat panel connected by DVI) ever since I put my computer together last summer. Happens maybe 5% of the time, and a reboot fixes it, haven't really had time up to now to investigate further.
Also happens when using an older screen connected by VGA.
Any ideas?
Many thanks,
Ian

 

[id_wright]

Sorry, wasn't very clear. Happens about 5% of the time when cold-booting, restarting or waking from hibernation (basically anytime the initial Abit screen normally shows during POST). If the screen displays the Abit POST image, it then goes on to boot normally. If the screen remains blank, the monitor power light flashes (as it does when the screen isn't receiving a signal), I press reset and then it normally works fine.
Hope that makes a bit more sense.
If it is a hardware error as mentioned above, is that likely to be in the graphics card?

 

[id_wright]

Have a system speaker, no beep when the screen doesn't work and single beep when it does (I think). This only started occurring after I switched graphics cards last summer though, so unless I did some damage swapping components around...
Many thanks for the replies.

 

[id_wright]

Have a Corsair 520W modular PSU.
Will check connections etc tomorrow.
Thanks for the advice.