The problem may not be as easily solved however if it is found that the boot sector ends up seeing a "boot sector unwritable" type error. The first thing you may have missed when trying the MS instructions however is a possible need to run the Startup repair tool a few more times to insure it finishes any repair it could make. IF and I say if the drive is seeing bad sectors at the front end you may be in for a disappointment however.
As of late for a friend on an older build with a drive now 6-7yrs. old in fact while it can still be seen at times with brand new drives as well as ones worn from use the Disk Check tool was run while booted live from the previous version's Vista dvd to run the "chkdsk c: /f" command at the command prompt option when suddenly seeing that type of error and Windows constantly failing to boot even after the last known to work had been used the last time the desktop was seen. A new drive had to be ordered.
That's the worst possible end. You may want to run a hard drive diagnostics tools to either confirm or be able to rule the drive out as the problem before anything else at this point. If the drive is found to good and troublefree the rest would be software/OS related which is better.
W7 Ultimate x64/W10 Pro x64/W11 Pro Triple Boot - Main PC W7 Remote PC Micro ATX W7 Pro x64/W11 Pro
CPU
AMD Phenom II X4 975 Deneb 3.6ghz - 965 2nd remote pc
Motherboard
Gigabyte GA-790XTA-UD4-Gigabyte GA-880GM-D2H remote pc
Memory
Kingston Hyper X DDR3 1600 1.5v 16gb - Hyper X Fury 8gb 2nd
Graphics Card(s)
MSI HD Radeon 5750 1gb - MSI HD Radeon 6450 on mini tower
Sound Card
Creative Labs X-Fi Xtreme Audio P - Realtek onooard 2nd case
Monitor(s) Displays
ASUS VW199T-P 19" HP 2082a Main-HP 2082a 20" remote pc
Screen Resolution
Asus 1440x900 - HP 1600x900
Hard Drives
WD Black 1TB HD per OS W7, W10, and pending W11 presently on 500gb OS Drive - Pending Triple 1TB HDs for Spanned Storage/backup volume
Single 2TB external USB enclosure, single 1TB System 7 Host/Boot drive, Pending 8TB external HD for system image b
PSU
Corsair 750TX - primary / Corsair CX600 - second
Case
Antec 900-2 - SSD compatible / NZXT Vulcan mini tower
Work through these steps for Troubleshooting Windows 7 Failure to Start
which try everything possible to start unbootable Win7, leading up to if necessary rescuiing your files to run Factory Recovery or get the superior Clean Reinstall.
Everything you need is there but report back results as we may have shortcuts or other steps to suggest.
