in reply to redirecting stdin on windows
What you're asking to do doesn't require Perl at all - the shell can already do it. Create a text file with the username on one line and the password on the next <insert speech about how you shouldn't store passwords in plaintext>. Then, you can simply do myexe.exe < answer.txt where answer.txt is the "answer file" you created.
If you really wanted to get Perl involved for some other reason, you could do this same thing from a call to system.
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