At this point the assistance of the System Security forum can be requested to provide guidance on a diagnostic tool to run a scan in the RE(covery) environment.
Scan results will determine the next course of action.
If marking 100mb Active fails to Repair x3, then mark Win7 partition itself Active and try above steps again.
A UEFI install has a EFI System partition instead of System Reserved, and a (hidden) MSR partition, can only boot from a GPT disk.Confirm using Diskpart commands or free Partition Wizard CD that these partitions are intact and run Disk Check on all of them including Win7 partition.To see a picture of your drive map with listings, download free Partition Wizard bootable CD to burn to CD with Windows Image Burner or write to flash stick.Boot to Explore C to see if your files are intact, post back a camera snap of drive map here for more help since often the problem is obvious to us.Only the System partition booting the OS should be marked Active.
A UEFI install to GPT disk must have its installation media or Repair CD booted as a UEFI device.
Then from System Recovery Options run Startup Repair and if necessary System Restore.
Make sure the Win7 HD is set first to boot in BIOS setup.
If you cannot get into Safe Mode then you can also try booting to run a full scan with one of the FREE Bootable Anti Virus Rescue CDs - Download List .
If running Malwarebytes in Safe Mode with Networking or AV boot disk scan does not work to rule out malware as a cause for the computer not starting, the Recovery Environment (RE) is an available option to disinfect Windows 7.
If no installation shows up to repair on an MBR (non-UEFI) install when booting into DVD System Recovery Options or Repair CD, or Startup Repair won't work after several tries, click through to System Recovery Options, open a Command Line to run these commands which should take care of corrupted boot records and blinking cursor problems: .