flickering 'artefacts' on some parts of screen

[alexeix]

Area: Media Portal
MP Version: 0.2 RC4
Windows Version: Windows XP SP2, all latest patches
CPU Type: AMD Athlon64 3200+
Memory: 1GB Crucial DDR3200
Motherboard Chipset: Shuttle FN95V2
Video Card: ATI Radeon 9600XT 256MB
TV Card: Compro Videomate DVB-T300 hybrid analogue/digital

Shuttle SN95G5V2, Seagate Barracuda 7200 200GB.

Synopsis:

When running Media Portal, there are what appears to be large artefacts flickering on and off, in the bottom right hand corner of the screen.

Upon closer inspection, it seems that it is actually part of the application which is running underneath Media Portal; in this case, Firefox. So I can see part of the web page flickering onto Media Portal.

When I move the mouse pointer up to the top left of the screen, where the power ON/OFF buttons are displayed, I can see further flickering, which shows part of the web browser address bar.

Furthermore, when browsing the EPG and trying to click on the aforementioned ON/OFF buttons, I have to position the pointer below (and sometimes to the side) of where I actually want the pointer to be, before the required button is highlighted.

I don't know if the two issues are related.
I've searched the support forum, but can't find other reports of this problem.

I have Google Widgets installed, in case that's relevant.

I do have a number of background processes running, e.g. Windows Defender, Friewall, AV, remote control software, ATI Catalyst, Spywareblaster, SpywareGuard, etc.
Could that be the cause? Are there any recommendations for what background processes should be running when using Media Portal?

Any suggestions?