Windows 7 I installed W7 on my mac laptop and worked fine, try to do it on iMac wont work??

[Chessh2036]

I just installed Windows 7 on my mac laptop and when i try to do the SAME EXACT thing on my imac it turns black and says 1. 2. press boot options and it wont work.

can somebody please tell me what is going on? They are on the exact same OS, it makes no since why 1 would work and the other not?