Boot up Display error

Hi all,

Not sure if this is the correct place for this.

Saturday (6/7/08), my system started Displaying an error when booting up.
After pressing the power button i get a message saying;
"DVI-D Can not Display this mode"
After trial & error, I now can bypass this and get into Windows XP by pressing F1 waiting a few seconds and then hitting the enter button to select the first boot option; which is XP. Once my system is almost finished booting up windows will appear and everything works fine. I can even restart my system and get into the bios.
The only thing that changed before this started was one windows update and a new Linksys Router.
Changed from a wireless G to a wireless N Gigabit (including installing monitoring software).

Has anyone seen this and how do I fix it?
Thanks

My spec's are:
ASUS P5N-E SLI / E6850 OC'd to 3.2(fsb 1450)
Silverstone case / Ulta 800 p/s
Dual boot - XP Pro / Vista 64 Home Prem
Two Segate Sata HD's (400 XP & 500 Vista)
Two DVD Burners

Just to give you all an update. It seem to be Linksys network advisor software that was the problem. would have never found out except my new Linksys gagabit router failed 14days after installing it. Took it back for an exchange but Fry's didn't have anymore in stock so I chose the D-link Gagabit gaming router instead. Had to uninstall linksys network advisor since it not compatible with d-link. Now everything back to normal.