If you have the option, upgrade to Windows 10/11 for repair operations. Microsoft has effectively abandoned DISM servicing for Windows 7 as of January 2023. Have a different error code? Let me know in the comments below.
DISM /Online /Cleanup-Image /RestoreHealth /Source:WIM:X:\Sources\Install.wim:1 /LimitAccess (Replace X: with your DVD drive letter)
DISM /Online /Cleanup-Image /RestoreHealth You need to point DISM to a mounted install.wim file from your Windows 7 DVD or ISO.

