That's the easy way to open mailto links in google chrome :
Open Regedit (*windows button* + R --> regedit)
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mailto\shell\open\command\
edit (default) to :
"C:\Users\*username*\AppData\Local\Google\Chrome\Application\chrome.exe"
https://mail.google.com/mail?extsrc=mailto&url=%1
That's it !
Have FUN !