a couple of my posts state that I'm using a WG 25K7197
I was using the LCD to install the card and drivers. I did alot of extra work to NOT play on a LCD.
Ultimarc sites says the arcadevga card may not work with all Dell PCs
I'm afraid Marc wont be able to help me. Unfortunately I bought the card without reading that part
any reason why the monitor would display like that with the nvidia card and soft15?
Ah! That explains it then

Now I understand...sorry for being slow to catch on.
I had a similiar issue when using my LCD to install drivers and then switching to my WG D9800...the problem is as I alluded to in my previous post. Your ATI driver now thinks you have two monitors connected...your LCD is still thought of as your primary so when you plug in just your arcade it goes out of sync...
You will need to have both connected and switch over to make your Arcade monitor your primary..I did this as well and it was fine after that. If the LCD wont work as you stated because of a Dell incompatibility you will need to temporarily use a higher resolution monitor to adjust the driver setting...or remove it in safe mode and reconnect using only your arcade monitor.
As for the Nvidia...which card are you using? That plays a *big* role in determining success with Soft15khz...also what Nvidia driver?
There is a thread that Sailorsat has on the german site that shows which cards are compatible and with what drivers or if a dongle (newer nvidia cards) is required.