if you make the USB Installer on another Mac then yes but i am afraid that OSX is a must. As for Win7 if you re-install it you just have to re-enable the OSX partition to boot Chameleon from.

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MSI P5Q / C2D E8400 @ 3.0 Ghz / 8GB DDR2 800Mhz / PCIe ECS 9600GT 1Gb / ALC1200 / Windows 7 / OS X 10.8
ASUS K50IN (SX004L) / C2D T6400 @ 2.0 Ghz / 4GB DDR2 800Mhz / nVidia G102M 512Mb / 15.6" HD/LED / ALC662 / Dell 1490 802.11g / Windows 7 / OS X 10.8