W7 Repair-Instal using OEM W7+SP1 Disc

I need to do a repair on my computer having damaged files that SFC /SCANNOW revealed but didn't fix. Considering doing a Repair-Instal to a system running W7x32 Ultimate is fully updated. Doing the Repair-Instal using the In Windows method and Upgrading to me is not an Upgrade because can't Upgrade from W7 Ultimate to a new version of W7, there isn't one. So, as there is SP1 installed in the computer if the download doesn't contain the SP1 then I am trying to Repair -Instal to an Operating system that is newer than that which is on the downloaded ISO.I would have to uninstal SP1 from my computer and get an W7 Ultimate x86 ISO having SP1 to use to do the Repair Instal. Correct?
Considering getting the W7 download from https://www.microsoft.com/en-us/soft...nload/windows7

Using this method described in the link below isn't an Upgrade.Or am I wrong? I ask because when I tried to do a repair-instal to a computer I had 8 year ago that had WXP Pro x32 updated with SP1 it would not allow me to do a Instal-Repair for the reason I stated above. This is for a friend whose computer has damaged system files according to SFC /SCANNOW and it didn't repair the damaged files. I know there is a way to repair/replace damaged system files using Log created with SFC /SCANNOW to show the damaged files, the OS disc and Command Prompts to replace the damaged files with good ones on the OS Disc. Also, this "In Windows" Repair-Instal is meant to leave all installed Programs/ Settings in place and create a Win Old folder containing data files etc so they can be moved back to their places in the 'Fresh installation" before the Old folder/s are deleted. Oh and finally, there is only 20GB of space available to use from 100GB of the only HDD in the Laptop...is that enough free space to perform the 'Upgrade' Repai-Instal. Thanks in advance

 

Might try Fred Langa's "Win7's no-reformat, nondestructive reinstall." It's a fast, nondestructive, in-place, total reinstall of Windows 7 that won't damage your user accounts, data, installed programs, or system drivers.