Firstly, you didn't fix the Input statements that should be Disp.
Secondly, your If statements aren't quite right. The way it's currently written, the program will always Stop because there is no Then after the test for A=1.
You should also generally use Return over Stop. It's a bit more stable and can be used within subprograms to return to the program that called it; Stop will stop everything.
:Input "Enter 1 or 2 to play this game ", A
:If A=1
:Then
:Disp "Deleting all data...Data deleted"
:Return
:End
:If A=2
:Disp "Warning...Data breached...System has been hacked"
The second If does not need a then because there is only one line after it that needs to be executed conditionally. You could actually shorten this to not even need a Return or Then statement.
:Input "Enter 1 or 2 to play this game ", A
:If A=1
:Disp "Deleting all data...Data deleted"
:If A=2
:Disp "Warning...Data breached...System has been hacked"
Short and sweet. The code will do nothing if A is not 1 or 2.