In your position, I would probably install at least these:

• Install PAR This will allow you to package your scripts into a self-contained "executable" (there's a bit more to it than that...).
• You will have to come up with a way to run a webserver locally, people have suggested for example HTTP::Daemon
• For BLAST searches locally, you will need to install the NCBI tools for windows: blast-2.2.11-ia32-win32.exe or possibly netblast if you just want to blast against remote databases.
• Then, to make perl talk to blast, I think this might be handy: Bio::Tools::Run::StandAloneBlast