Boot camp on iMac 2011?

So I have been working pretty hard putting windows 7 on my macs and I successfully got windows 7 on my MacBook Pro (late 2012) but my imac is having trouble. It is a 2011, and I created a windows 7 install disk on my flash drive that worked for my macbook but when I try to do it on my imac I get a black screen saying No Bootable disk, please insert a disk and press any key. I've done lots of research and can't seem to find an answer. I hold in alt when starting up and can boot Mac OS but there is Not a Windows partition there. Also I had to edite the plist file so I could create a windows install disk. Could the plist be the problem

I'm using boot camp

Thanks in advance