Win7 system can not boot safe mode can not get stuck in disk.sys how to do

Analysis of the cause:
This type of problem is generally caused by the partition format has not been successfully converted into MBR format, please backup the data here, and then use the pure installation version of the installation media, you can use the command conversion format.
Scope:
ThinkPad, pre-installed Win8, pre-installed Linux, Win7
Safe mode failure diagram:

Operation steps:
1, use DiskPart tool to re-partition . First use the Windows 7 CD or U disk to boot, enter the system installation interface;
2, in the interface of the selected partition on the keyboard press "ldft; F10" or "ldft + Fn + F10"; Open the command prompt window;
3, in the open window, enter the following commands in turn, each time you enter a line, press Enter, the specific operation commands are as follows;
diskpart
select disk 0
clean
convert mbr
exit
4, then close the CMD window, then refresh the repartition, and then reinstall the system.