If I understand the question correctly, you are describing the malfunction of two specific keys on your keyboard. If this is the case, you probably need to replace the keyboard. The two keys work 100% fine in other shortcuts and in single use. its just this one shortcut.
F5
Windows logo key + E
Try clicking the window that you are working in, that helps sometimes.
It is not clear what you mean by "tab," but if you are talking about a window, then there is no shortcut for Excel to minimize or maximize a window. You need to click on the symbols in the top right corner of the window to maximize or minimize.
Alt + F4 to close the active application window, or, if no window is open, shut down Windows
In order to create a desktop shortcut for Paint in Windows XP, you will need to go to: Start > Accessories and Right Click on Paint. From the new window, click on "Send to Desktop (Create Shortcut)". Paint should now be available from the desktop.
The keyboard shortcut function control-w or ctrl-w closes the window of the program you're in. It's the opposite of ctrl-n, which opens a new window.
by double click shortcut on the desktop.
Alt + Tab, Win or Ctrl+Esc, Alt+F4, and Ctrl+Alt+Del
Check the power window fuses and the relay first. If all of the windows do not work then it is a power problem with the whole window system.
ALT+F4. A lot of window managers and desktop environments on Linux also use this shortcut.
[Ctrl]+[Q] (Quit) On a Windows operating system [Alt] [F4] will close the active window.