<p>Apple says you need the Windows 7 install discs;
[Boot</a> Camp: Windows 7 installation frequently asked questions](<a href=“http://support.apple.com/kb/HT3986]Boot”>Install Windows 7 on your Mac using Boot Camp - Apple Support)</p>
<p>Looks like there is a work around here;
[Installing</a> Windows 7 Without Using DVD/USB Drive [Method 2]](<a href=“http://www.intowindows.com/installing-windows-7-without-using-dvdusb-drive-method-2/]Installing”>Installing Windows 7 Without Using DVD/USB Drive)</p>