How can I open more than 15 files at once on Windows 7?

Solution 1:

Open regedit and navigate to:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer

Add this case-sensitive DWORD (32-bit) key:

MultipleInvokePromptMinimum

Set the value to

16

P.S. 16 is not a hard number, but actually indicates "unlimited", so putting in 17 probably will not work.