Start Windows 7 and fix MBR (grub rescue entry after Windows 7 and Linux are deleted)

Cause: My laptop was originally installed with Win7 + Linux, and yesterday I found that the hard disk was not enough (only 60 GB, although there was still a GB mobile hard disk ), I just want to put the Ubuntu in it. Most of them are tested using virtual machines. Later, the partition of Ubuntu was defined. After the restart, the command window: grub rescue: _ appears. Remember to rewrite mbr.
Solution:
1. Insert the win7 installation disk into the optical drive or start it with USB (win7 supports USB Direct start and installation );
2. After selecting the language option, go to the next step and select the system Repair Option below instead of continuing the installation;
3. After Automatically Searching for the installed system, go to the next step;
4. Do not enable automatic repair in Windows. If it is useless, enter the command prompt mode;
5. Enter the bootrec/fixmbr command and press enter, and then enter the bootrec/fixboot command to press Enter;
6. restart the system to restart the Win7 startup mode.