Advice on a pc and content creation

I am currently setting up a digital advertising network selling adspace to local businesses. I will also be putting hd video on the screen. Can somebody tell me is the pc below good enough to power this. I intend to have 40 ads plus running on these pc's. Can anyone direct me to somewhere that i can get pc's of this quality cheap. I am also looking for a very good designer for creating ads for my customers. I also want to create a few ads myself. What is the simplest software and the best to use free or cheap. I am from Ireland so keep this in mind if you are showing me pc's with a us power supply.

http://www.adverts.ie/293935/desktops/windows-7-media-centre-full-hd-hdmi-p2-m2a690g-am2-7850-2gb-ram-340gb-hd-asus-pundit/

Any PC with a 2.5GHz Dual Core2 or better with 1G of memory is fine.
And for content creation, be sure to visit http://BluePony.com

And, you can also check our FAQs under support section of the MediaSignage web site for a list of the minimum requirememts.

David - MediaSignage.com