Switch win8 under thinkpad to win7

Switch win8 under thinkpad to win7
Preface:
Recently, I bought a thinkpad notebook from the Internet and preinstalled the win8 system. The user experience of the win8 system is good, but it is not enough for our programmers. For example, I still cannot use a virtual machine, cannot be correctly configured. I think win8 compatibility may not be enough, so I want to change it to win7, so I will try again.
I used to install the system with a USB flash drive, but I couldn't install it this time because the disk format is gpt rather than the mbr that I used to use (now the computer is advanced and I never considered this situation before ), therefore, ghost cannot be used! How can this problem be solved? It is to replace all partitions, convert the disk format to the mbr format, and then the system can be installed normally! (My initial thought was to install win7 to another disk. After all, win8 has a good user experience !) The conversion steps are as follows,