Some short cut keys do not work suddenly

Hello, today I opened blender and found some shortcut keys did not work.
For example, if I press Akey, it switches the layers instead of selecting all/deselect.
Other keys that I have noticed are Z, B, Shift+D…
Looks like Ctrl+R and Ctrl+Z works.
I am using the default settings of blender2.5.

I installed Norton on my computer yesterday, and that is the only cause I can guess.
Because blender was working fine until yesterday.
Does anyone know how to fix this and the cause?


Addition:
Found when I type in any textbox in blender, every alphabet key turns into a number.
I can type any sequence of letters and it will be in numerical order like 123456… but start on a random number and then repeat.
That’s why the shortcut keys won’t work.
It is fine in all of my other programs though.

This problem was solved!
Just removed a program which caused this problem.
Last night, I had to install Constant Guard to install Norton.
But after I removed Constant Guard, everything went back normal.