Ok, then i may have a problem, as i have a vga to scart cable, and have just tried it on my TV, put the picture scrolls really fast (something to do with V sync???) I thought powerstrip may sort this problem, but if i cannot use it with the Ultimarc card then i dont know what to try
If you are using a regular the TV, the the arcadeVGA ouput will be compatible with it.
Your problem is almost definately not the output from your card, but in the connection from pc to tv or in the tv.
A vertically rolling picture suggests that the tv is not detected the vsync correctly. Some tv's expect a composite sync, some expect seperate, several can deal with both. You can (I believe) just physically connect the H and V sync output from the VGA card together to get a composite sync that will work (this is not technically perfect, but I think the arcadeVGA uses negative syncs so you can do this). If you have just purchased a VGA to scart lead then the chances are good that it does not do this.
The first thing I would do is check wiring of your VGA to SCART lead. If you satisfy yourself that it is all wired correctly and the syncs are getting to the tv, the next step I would take would be to open the scart connecter and wire the H and V syncs together with a peice of wire, and then test....
Hope that helps...