What is the purpose of your for loop? Since you're using 2→A at the start of the loop, A will have the same value every time the loop is run, and the only thing that will happen when you run the loop more than once is that the what you've already drawn will be drawn on top on itself.

The code can also be rewritten to save space by using other for loops.

:ClrHome
:Output(1,1,"DELETING RAM
:For(A,1,16
:Output(2,A,".
:rand(15
:End
:Output(3,1,"RAM DELETED
:For(A,1,16
:Output(4,A,".
:rand(15
:End
:Output(5,1,"DESTROYING
:For(A,1,16
:Output(6,A,".
:rand(15
:End
:Output(7,1,"VIRUS FINISH
:For(A,1,16
:Output(8,A,".
:rand(15
:End
Or even like this:

:ClrHome
:For(B,2,8,2
:If B=2
:Output(1,1,"DELETING RAM
:If B=4
:Output(3,1,"RAM DELETED
:If B=6
:Output(5,1,"DESTROYING
:If B=8
:Output(7,1,"VIRUS FINISH
:For(A,1,16
:Output(B,A,".
:rand(15
:End
:End