Setting defaults in Explorer

Is there a way to set the default when opening explorer or in other windows programs to a user defined folder?

Yes, you just need to modify the target property.

Right click on the Windows Explorer icon in the taskbar, then right click on "Windows Explorer" in the jump list, then click on "Properties". Click on the "Shortcut" tab, then modify the "Target" field value to the following:

%windir%\explorer.exe /n, /e, <New Path>

where the <New Path> parameter represents the path to the folder that you want Windows Explorer to open by default. Note the spaces and the commas. The following is an example:

%windir%\explorer.exe /n, /e, C:\Billdocs\

where C:\Billdocs\ is the folder you wish to open by default.