How to load windows 7 directly (without Boot camp) in a Mac Mini with intel processor whose Hard disk crashed and so is replaced?
Just because something isn't documented doesn't mean it is impossible, the following is true for Mac Mini's from 2010, 2011 and 2012. 

You can install Windows alone on all three by configuring a hard drive to be MBR, setting the active partition to be the one containing the Windows folders. A Boot Manager, the 100mb partition you see on windows 7 computers, can be configured to point to this installation or better yet boot the mac holding C and boot into the windows 7 install CD. Have it repair the installation, it will create this partition pointing to Windows. 

The drivers are difficult to find, however, you can buy a Mac and do everything needed in Windows without having to have any apple software loaded on the machine.