I'm very happy to finally be able to watch Freeview-HD without display issues :)
For those with AMD chipset motherboards, you now have to separately download the chipset drivers. At the AMD/ATI download page, select Integrated/Motherboard option and select closest match chipset & Go. Scroll down to the "additional downloads" section and download the "South Bridge Driver". This contains the Northbridge Filter, IDE Controller, and SATA RAID Controller.
AMD Athlon X2 4200+, Gigabyte GA-MA770-DS3 mobo, 2GB RAM, 1TB SATA HDD, DigitalNow Dual Hybrid PCIE S2 (DVB-T) capture, ATI 550 (PAL) capture, ATI HD3650 video with HDMI-HDMI to 32" LCD TV at 1360x768, Vista Home Premium 32bit SP1, Cyberlink PowerDVD8 Ultra (patch 1830), GBPVR with EVR renderer