Hi,
Thank you for contacting Microsoft Community.
I appreciate your time and effort.
I understand that you are unable to use few key combination.
I will certainly help you with this.
You cannot change the function for control alt delete keys this is by default on windows.
I would like to inform you that you can use the stick key for easily access the keyboard buttons:
a. Click on Control Panel from the start button on bottom left.
b. Click on Ease of access.
c. Click on Ease of access center.
d. Click on Make the keyboard easier to use.
e. Under make it easier to type.
f. Click on setup up stick key.
g. And choose the option according to your convenience.
Also refer the link:
http://windows.microsoft.com/en-in/windows/make-keyboard-easier-to-use#1TC=windows-7
I hope this helps. Please let us know the results. Feel free to write us back for any further assistance with Windows, we’ll be glad to assist you.