Hi Talita
Many thanks for your kind reply. That does work and puts the correct theme in place - which I thought was the aero.theme in C:\Windows\resources\Themes.
I can find the aero.theme file in resources\Themes but if I double click it and Open it, when it applied itself it looked different from when I applied it in the settings page. Most notably, the taskbar is a pale grey, whereas when I change it on the settings panel it is dark grey which is what I want.
I am trying to change the [Control Panel\Colors] item to add a specific colour to backgrounds in apps. e.g. Window=230 255 255 but when I put aero.theme in my own themes folder it still seems to make the taskbar light.
If I make it a High Contrast theme it colours too many things but does include the browser background as well as other apps which is partly what I am looking for. However it goes too far and overrides all background colours on webpages and makes the sidebars and tabs white instead of keeping the aero grey which was fine.
Today it has actually been behaving differently so the aero.theme file may just be OK and is applying the dark grey task bar so I am not sure what has changed! I guess what I need is to be able to get better control of specific elements of the theme.
Sorry if I have wasted your time but re-exploring this has helped alot in the light of your comments. If you have any pointers on theme development and what controls what that would be great.
One other problem is when I download a theme it gives the warning about unsafe content - is there an easy way I can codesign theme files which are genrated "on the fly" so don't exist as files until they are generated?
Many thanks for your help - it is much appreciated.
Best Regards
Steve