|"I've disabled the Nvidia card in device mgr and rebooted"|
What nVidia card are you referring to? Since you have an ATI card, you'll have to remove the nVidia card & uninstall the drivers before installing the ATI card & Catalyst drivers. You do NOT have to disable anything in Device Manager. In fact, you screwed yourself by doing so. See if you can boot into safe mode & re-enable it. Then uninstall it the right way.
The EAX300 is an extremely low end card. Considering the rest of your specs, why are you even bothering with such a weak card? Apparently gaming performance isn't a concern?
"There is one other PCI-E on this board but it is only up to x2"
If you're asking about the LANParty, it has two PCIe x16 slots but you can NOT mix ATI & nVidia cards.
"If my answers frighten you then you should cease asking scary questions" - Jules Winnfield (Samuel L. Jackson) in Pulp Fiction