Win7 can't start until the driver signature is forced. This is caused by the loss of system startup components, which can be solved by reinstalling the system:

1. Start the computer to enter the system desktop, then open the folder of the storage system image, and double-click the system installer to enter the system installation process:

2. Then, select the disk location in the pop-up window. Here, select disk c:

3. Select Yes in the dialog box:

4. When the window prompts whether to restart the computer, select Yes:

5. Finally, after the computer is restarted, you can enter the system normally without errors: