Customizing file explorer

I've searched Brink's tutorials and haven't found what I'm sure must be there--so a link from someone would be handy.

1. I'd like to set an explorer taskbar (or any explorer) shortcut to open a certain folder by default. I inserted 'C:\MyStuff' in Properties/Start In but that doesn't work?

2. I had dragged the 'name' explorer from under Accessories at some earlier point thinking that would create a copy--it did not. Now there is no explorer located under accessories. If I were to replace that shortcut with another would I have to go find explorer.exe and do so from there?

3. I did have a shortcut located on my Rocketbar that I could click more than once to create more than one instance of explorer--but I cannot do that with the taskbar shortcut. What had I previously done differently to allow multiple instances?

Thanks as usual + this is still a work in progress--to wit, I've managed to stick explorer.exe (not a shortcut) on the desktop .

Unless pressed, I'll avoid describing the 'how I managed this' maneuver. So where does the exe belong so I can move it back home?

Thanks,

Mark

I attempted to cut/paste C:\Users\Mark\Desktop\explorer.exe to C:\Windows. I was prompted 'overwrite'? (meaning there's at least 2 instances of the exe). I said 'yes' but the operation would not complete.

Confirming at least these 2 instances--

C:\Windows\explorer.exe
C:\Users\Mark\Desktop\explorer.exe

?

The exe is definitely in both locations--same file size. I must have made a copy to the desktop. I'll delete the desktop instance.

Thanks--

Tried but no--unpinning from Start (unfortunately) doesn't replace my missing shortcut under Accessories.