odd shearing on LCD TV through PC input... similar to vsync problem?

[PardonTheWait]

I bought a Wharfedale LCD26HD tv yesterday, and I'm very pleased with all the aspects of it except the VGA and DVI inputs... When using either of those with my 2nd PC driving the display, there's a horizontal shearing when anything fast happens - like any DVD, or picking up windows and wiggling them about fast. It's in the same place all the time, it doesn't move. It's probably 1/3 down from the top at a guess.

Is there any way I can fix this? I've tried different options on the graphics card (Radeon 9250) but can't seem to fix it

If it's a problem with the actual input and can't be fixed, I'm gonna have to return it and get a Samsung, but if there's any way I can fix it I'd rather do that.

Any help would be much appreciated

 

[PardonTheWait]

Yes I have. That was my first though, the frequency.
In the DVI section of the manual it has '720p - 1280x720, horizontal freq 37.5 v freq 50hz'

then under that '720p 1280x720, h freq 45.0 and v freq 60hz'... could it be that it's trying to do the first (50hz) one?

 

[PardonTheWait]

Well the PC is set to 60hz but it's still shearing