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#11
Unplug PC, press power button and hold to drain residual power, replug and Power On.
See if Win7 will startup. If not, tap F8 key repeatedly to access Repair console. Accept any offered Repair; if necessary boot back in to try Startup Repair from the Recovery Tools list repeatedly. SysRestore should be offered - if not try running it from list. System Recovery Options
If not, reboot and press F11 key repeatedly to trigger Factory Recovery. Choose a full format destructive recovery which will wipe and reinstall all but the Recov partition (only Roadrunner can erase himself).