I have an AMD X2 3800+ system, which until a few days ago had a 7800 GT video card, and now I have an 880GTS 512 MB card. Prior to the new card I was able to run, albiet slowly, City of Heroes on my system with dual screens. 1. Viewsonic VX 924 & the other monitor is a the BenQ 241VW. But now with the 8800 I am unable to run City of heroes in dual display mode (i.e. DualView). When I try, the game locks and the CPU usage spikes at 100% until I end task the game.

Windows XP Service Pack 2, with Direct X9.0c
Drivers : 6.14.11.6906
& even tried the latest and greast drivers.

Any thoughts on the cause, or resolution?

Ram?
U didn't state the amount of system (hardware) ram.

Most games dont support Dual Monitor.

2 GB of RAM.

As for dual monitor and the game...I am not saying I want to run the game on both screens...what I do want is to run the game on one screen and watch a DVD on the other.

I have done it with my P4, nvidia 6800 GT AGP system with 2GB's of RAM no problem... but my 8800 GT with my AMD system won't seem to do it?

I have this same problem. I used to be able to run COH, and have my other screen up. I had the 7900GTX. Swapped to the 8800, and now, the game will start, and I will get to the character selection screen, but when I change characters, it locks the system up.

Turning off dual mode is the only fix I have found so far.

your best bet is to go ati cuz i has the same problem and it frusting. i play coh and use dual view, im a badge whore so i need to have the other monitor open. the best fix for tjhis if your not going to go ati is to go into system proteries and turn off the 2nd monitor in display properties load coh and after your in zone face your toon at a wall or near colorless area then tab+alt back into display porperties and turn on the 2nd screen both displays with flicker once or twice and you'll ahve you daul viwe and coh. i wih there was a toggle or hot key for this in nivida's profile setting i havent found it

i had an 8800gts 512 and was able to run dawn of war on my monitor and watch a dvd on my tv. but, i had to screw around with the display settings. i don't remember exactly what the settings were but it had a lot to do with separating the display resolutions and fine tuning the screens from there...

I had the exact same problem. New computer, same multiple monitors, runs everything brilliantly except COH.

It wouldn't even run windowed.

I found a setting in nView that fixed it.

In the applications tab add city of heroes to the list.

In the individual settings for coh uncheck the "Enable window spanning across multiple displays" option.

The wording on that option and the problems with it running on multiple monitors sounded pretty similar.

[addition]:
It looks like there is still a slight issue. When I run it dual screened there seems to be some texture corruption. When you mouse over something and the cursor would usually change color it just shows a black box. CoH must be trying to access the wrong memory when it has multiple screens and that setting just sort of fixed it. When I change it to a single display the cursor works fine.
[more]:
I don't really know now. I removed the setting and it still loaded. I can't really say for sure since it isn't crashing anymore when I go back to my old settings.