Vbox is free, it is an oracle product (acquired sun, has to say sun is a tragedy)
Official Website: https://www.virtualbox.org/
: Http://download.virtualbox.org/virtualbox/4.2.6/VirtualBox-4.2.6-82870-OSX.dmg
Install vbox, create a new virtual machine, select windows7, create a hard disk VDI, and select Dynamic Disk Space allocation
Click Settings, select the physical or ISO file in the optical drive option, and then click Start
After Windows 7 is installed, it needs to be activated. There is an active tool (which can be found online). The operation process is the same as normal installation. Set the m free partition disk number, activate it, and delete it.
If you want to use a USB flash drive, you also need to install the extension package. Address:
Http://download.virtualbox.org/virtualbox/4.2.6/Oracle_VM_VirtualBox_Extension_Pack-4.2.6-82870.vbox-extpack