Is there any way to disable screen shortcuts such as Ctrl+Alt+[F1..F4] in Windows 7?
There is no native way to disable hotkeys in Windows 7. (By the way: The shortcuts you mention are not default hotkeys by Windows 7.)
You can however use AutoHotkey to disable almost any keyboard shortcut. There are other utilities for this, but AutoHotkey is my weapon of choice.
You can disable the hotkeys mentioned here with the following code:
Just paste the code into an AutoHotkey script that you launch at startup and the keys will be permanently disabled.
If you want to reassign the hotkeys to something else, you can do as follows:
I happen to have provided an answer to a similar question: How do you disable hotkeys in Internet Explorer 9?
Similar thing happened to me. I happen to have an Intel display card.
There's an Intel Graphics and Media Control Panel that allows "Hot Key Functionality" to change various aspects of the display. One of the default hot keys is Ctrl-Alt-F1.