How do I set the Putty Window size to open bigger than the default?

When you open PuTTY select Window in the tree on the left:

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You can change the number of rows and columns in the Window here.

Alternatively, select Appearance and change the font size:

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Once you're happy with your settings, select Session and then save these settings back as "Default Settings":

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These settings will now be the default for new PuTTY windows.

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