Proxmox 3.4 Install Resolution Issue

Hello i have the Problem that i cannot install Proxmox.

The Installer Screen shown me only the left Screen - i cannot press continue.

I have try start with VGA=normal (etc 775,788 ....) - nothing changed.

I have search the Forum for this issue and found two or three Threads - but only with the answer "You have no Vesa 2 kompatibile VGA Card.

I have tried with AMD Onboard Graphic Card ( Radeon HD 7480D ) and with a NVIDIA PCI-e Grafic Card - always the same issue.

What can i do (Please i want not to install Debian first and then Proxmox over it)??

Maybe there is a soluton for my Problem?

And sorry for my bad english.

Thanks

HPK