Rectangle selection is one of the most time-saving tricks when editing large chunks of code, but the benefit is more or less lost if you have to reach for the mouse to do it.
In Visual Studio you can hold down the alt button and use your mouse to select a rectangle of text. You can also use Control + Shift + arrow key to do this with the keyboard. If those shortcuts do not work on your machine, go to Tools->Options->Environment->Keyboard and add shortcuts for the following commands:
Edit.LineDownExtendColumn
Edit.LineUpExtendColumn
Edit.CharLeftExtendColumn
Edit.CharRightExtendColumn
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