There are a couple ways to get to Mic Boost in Windows 7...
Rt Click on speaker icon (taskbar by clock) > Recording Devices - you get a (Sound) window, Microphone @ the top, highlight it, hit Properties button (bottom right corner), select Levels tab.. you will (now) see 2 sliders, 1 for volume & the other for boost.
OR type Sound in Search OR > Control Panel > Hardware & Sound > Sound. End up @ same as above. So @ least 3 ways.
Anyway it IS there (in Windows 7).