By default, your keyboard's numlock enabled number pad doesn't work well with console applications running on a PuTTY SSH connection. The numpad's numbers seem to get mapped to inserting the characters "q" thru "y". This is especially annoying when using vim.
To get numlock working, open PuTTY's configuration window, goto Terminal > Features. Enable the "Disable application keypad mode" checkbox.If you want this setting to persist, make sure to select a saved session and click "Save".