So I did a xen install on a dell PE R220 and then tried to do a simple Debian install from a cd. In the first instance it took about 10 minutes for the initial Debian splash screen then when it couldn’t connect to an apt mirror it froze, I tried shutting down the vm via XenCenter and it just got stuck and wouldn’t shutdown properly. I tied an external cd drive and had the same problems. After some cursing I dug out one of my trusty ML115 G5’s that was waiting patiently on a shelf. Installed Xen and Debian via CD with no issues at all!.