Alt/E/C and Alt/E/P to start with - Alt/E pulls down the edit menu, and "c" or "p" copies and pastes. Been using those commands since before I had a mouse. Late 1980's.
The keyboard accelerators for copy and paste have been ctrl+c and ctrl+v for 10 to 15 years.
But they work, in fact I just opened up 2007 and gave it a whirl to make sure so I wouldn’t sound dumb. When you hit Alt-E a drop down says continue with the Windows 2003 key sequence and the copy/past function continues as normal. I personally use a different method like ctrl-c, ctrl-v etc.