First try booting into Safe Mode with Networking
to install, update and run a full scan with Malwarebytes
. Then once cleaned run SFC -SCANNOW Command
and work through these troubleshooting steps
If Safe Mode is not working, download, burn to CD or write to flash stick, boot and run a full scan with Microsoft Standalone System Sweeper.
Once the System is clean if it won't start boot into System Recovery Options
via the F8 menu or disk as shown in tutorial, run Startup Repair
repeatedly no matter what it reports. Post back results.
If this fails, try System Restore from Recovery Options list, then if that fails open a Command Line to run SFC -SCANNOW Run in Command Prompt at Boot
As a last resort boot free Partition Wizard
bootable CD to Explore C to see if your files are intact, make sure C or the 100mb System Reserved partition (preferred) is marked Active
, then click on HD to highlight it, from Disk tab select Rebuild MBR, Apply. If Windows 7 doesn't start and you restored Active flag, run Startup Repair 3 Separate Times
If these all fail you can copy out your data using your Windows 7 DVD or Repair CD: Copy & Paste - in Windows Recovery Console
or Paragon Rescue CD. System Repair Disc - Create
Then run Factory Recovery from its partition or disks you made or order from Tech Support, or find a Windows 7 installation DVD to clean reinstall using Product Key on COA sticker: Clean Reinstalling Windows 7