Taskbar not Changing to Aero

Hi, sorry if this is the wrong place to post this, but I'm having trouble with my taskbar; It refuses to change to the transparent aero colour. Instead it remains in Windows Classic, while everything else is aero (the window borders are transparent still).
I've tried methods of forcing aero and have updated drivers but to no avail. I think it may be because I am running an ATI graphics card and an Nvidia one but I'm not sure. It's not too much of an issue it's just really ugly

Hi Beany, Windows 7 automatically adjusts Aero effects based on your computer’s Windows Experience Index on a scale of 1.0 to 7.9. The subscore for your computer’s graphics performance determines which Windows Aero effects are supported, so you could be right with your Graphics Card.

Yeah, I think it is a graphics card issue. It's not that I can't run Aero though (I score 7.8 in the windows index thing) It's simply that the taskbar refuses to change. It's quite strange.

Have you tried updating the driver for the graphics card?

Yeah, both cards were updated yesterday.

Hi Beany

Are you running a dual monitor setup?
Is this the reason you are using two graphics adapters?
If so try switching the Default Monitor in Display Settings, this may give different results with the Taskbar.

Hi, I'm using an Eyefinity setup. So while technically it is 3 monitors it is only recognised as one; all 3 monitors are the default. All 3 are connected to the single ATI card, while the other Nvidia card is purely for PhysX operations that some games implement.

There are some programs that disable Aero when they are in use, including my older version of Paint Shop Pro but you seem to be saying you have all the Aero effects but your taskbar. Does your start menu show the aero glass effect with no problems yet the taskbar is solid?

Have you tried changing to a non-Aero theme like Windows classic and then changing back again? Do you use any tools/tweakers like TuneUp Utilities 2010 which disable/modify registry settings for improved speed, etc and may have modified your settings? Has it been this way since you got it or was it working and then quit?

Having competing video card makers in the same machine is a bit unusual and I suppose it could be a compatibility issue.

Thanks for all the replies so far, in answer to the previous one:
-I don't think there are any programs causing the problem since I hadn't installed, or really changed, anything (at least not that I recall) when the issue started.
-If I change to any theme it adopts the wallpaper but says I'm in windows classic (but some aero effects still apply)
-I have some clean-up software but it's never been an issue.
-This problem occurred around the time I installed the other graphics card. Although not straight away. Before that it worked fine.

One weird thing is there is a transparent, aero line running along the top of the taskbar. The start menu isn't aero. Also, if two labels combine in the taskbar (i.e. having two of the same window open at once) when I click on them the text is invisible. It's all very frustrating, I can't even change to windows basic

I appreciate the help!

Looks like explorer.exe is buggy... Strange.

I have no idea what to do though...