Windows 7 64 causing HDTV to power cycle (turn off and on)

Hi all,

I hope someone can help with this problem as it is driving me slightly mad… I apologise if this is not in the right part of the forum but I couldn’t find a section that it seemed to fit into.

Firstly I’ll give you my set up details for some background:

Computer:
Windows 7 Ultimate 64
EVGA Nvidia 560 TI
HP 1080p monitor

Receiver:
Onkyo TX NR414

HDTV:
LG 42LW550T

The computer is connected to both the HP monitor (by DVI) and the Onkyo Receiver (DVI to HDMI cable). The receiver is then connected to the LG HDTV. Windows is set to duplicate the display on both screens, the resolution is set to 1080p 60hz which is meant to be the native resolution for both the monitor and the HDTV.

The problem I am having is that, when using the computer on the TV, it will sometimes cause the TV to power cycle (go into standby and then turn on again).

I also have a Sky HD box and Xbox 360 connected and never experience this issue with either of them, so I assume it must be computer related.

The main time this happens is within XBMC whilst watching a video, the screen will freeze (I can still hear sound), the TV power cycles and then comes back on. However, this has also happened whilst using the Dolphin Emulator and watching a game trailer in Steam (in Big Picture mode).

I have tried updating the video card drivers, rolling them back etc… but the problem persists. I have also tried different HDMI cables and HDMI ports etc...

I can only assume that something the computer is asking the TV to do is causing it to ‘reset’ but this is only a guess.

Any help with this would be appreciated as at the moment the HDTV connection is fairly useless.

Oh and I don’t know whether this is important but the Nvidia Control panel shows the connection as ‘TX NR414’, however, the Windows Display properties just shows ‘Generic PNP Monitor’.

Thanks

Jonathan

Just an update, this has now happened whilst just surfing the net, so it doesn't appear to be related to demanding video.