I am trying PM5 beta on a AMD based computer with Win 7 SP 1 (all latest updates). My current PM4.9 is active until November 2012 and is working as normal.
I have downloaded Beta today (29 July) and installed as Admin and set up permission for my User login. The install seemed to run as one would expect and the the program appears in the program list in control panel and the shortcut icon is on the desktop. I am having no problem with any other photo software, LR4, Qimage, Irfanview, etc.
CPU Type: HexaCore AMD Phenom II X6 1045T, 3139
Motherboard Name: Asus Crosshair IV Formula (2 PCI, 4 PCI-E x16, 4 DDR3 DIMM, Audio, Gigabit LAN, IEEE-1394)