This may help: Register Windows Live Hotmail with the Default Programs tool in Windows Vista
Vista and 7 have many similarities. It doesn't seem logical for Microsoft to require the installation of a mail application just to use web-based email. The above (at least for Vista) is supposed to enable you to make Hotmail the default for sending email within the web browser environment (i.e. mailto: ).
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
OQO 2+
OS
Windows 8 Pro w/MC 32-bit
CPU
Intel Atom 1.86 GHz
Motherboard
OQO 2+
Memory
2 GB
Graphics Card(s)
Intel GMA 500
Sound Card
IDT
Monitor(s) Displays
LCD
Screen Resolution
800 x 480 (portable) 1280 x 1024 (docked)
Hard Drives
64 GB SSD
PSU
9 Ah Battery (portable) or OQO Brick (docked)
Case
Shirt Pocket Sized
Cooling
Tiny Fan
Keyboard
Slide out (portable) DiNovo Edge (docked)
Mouse
Eraser head (portable) Logitech Bluetooth (docked)