I was today stuck in a 2003 VM for a while…. no intergration AGHr…. here some things that are REALLY helpful. :o)

Standard: CTRL + ALT + DEL 
VMC: CTRL + ALT + END 
Displays the Task Manager or Windows Security dialog box on Windows (or logs in).

Standard: ALT + TAB 
VMC: ALT + PAGE UP 
Switches between programs from left to right.

Standard: ALT + SHIFT + TAB 
VMC: ALT + PAGE DOWN 
Switches between programs from right to left.

Standard: ALT + ESC 
VMC: ALT + INSERT 
Cycles through the programs in the order they were started.

Standard: CTRL + ESC 
VMC: ALT + HOME 
Displays the Windows Start menu.

Standard: N/A 
VMC: CTRL + ALT + PAUSE 
Changes the Virtual Machine Connection window to / from full screen mode.

Standard: N/A 
VMC: CTRL + ALT + LEFT ARROW 
Releases mouse and keyboard focus from the Virtual Machine Connection window.