Deleteing a layout in xsi 2.0.x is very easy:
Go to View->Taskbar
Now you should see a small bar to the left with a button for each layout you have installed. To delete a layout, simply right-click on one of the layouts and select "Remove Layout". Also, if you want to install or export layouts from different systems go to: File->Add-on and select one of the options from that menu.
Hope this helps
-Andreas