after a bit of tweaking via bgconfig it worked like a charm.
Did the vanilla installs work with all defaults in bgconfig, with just putting the hardware sliders on full?
What did you change in bgconfig?
Then I managed to work out how to install Unfinished Business and I'm assuming it worked (I selected the components I wanted to install and launched the game again successfully), though I haven't played the game yet to test it.
If it installed correctly you will see it listed in the WeiDU.log
Then I tried to install the widescreen mod and everything went pear-shaped.
I double-clicked on the widescreen application and pointed it towards C:\Games\BGTutu and a box came up asking me what resolution I wanted. I have a 16:9 monitor and chose 960*540 because I want to lose the black borders but I still want to see detail on armour and weapons etc. and don't want to be zoomed too far out. I assumed it would have installed correctly but when I double-click on my desktop icon I get an instant CTD.
Your problem is you chose a resolution your monitor can't display.
The lowest 16:9 will be 1280x720.
Right click on your desktop/ screen resolution/ advanced settings/ list all modes. (thats what you get to chose from)
You could play 800x600 & lose the black bars by adjusting the scaling to full screen in the Nvidia Control Panel.
But it will pull it out of shape a bit.
So I decided to uninstall BGTutu and start again, but to my horror it does not appear in the Programs list (Control Panel > Programs), so I don't know where it is ! I'm assuming that simply deleting my BGTutu folder will not uninstall the game ?
That is because TuTu is basically just a BG2 Mod.
Yes you could just delete the TuTu directory.
But you probably need to just go into your TuTu root directory & run setup-widescreen.exe & uninstall it.
Then run it again an chose a resolution supported by your monitor/displaycard.