Solver is Excel add-in. If you want to remove it go to Excel Application > Options > Search for add-ins > Press something like 'go to' button > un-check Solver on the list (I can't give you exact path as I have Polish version of Excel).
It's better not to try to open Solver's VBA code as it is rather copyright protected.
Moreover, I don't think Solver makes any inconveniences when working with Excel or VBA.