Stalled Win7 install log file location
Google the last entries to find out what may be stalling out the Repair install.
Try establishing a Clean Boot which can also help with performance problems. Having an OS "overloaded" with programs is never a good thing so I would prune them as best you can or at least turn them off from starting with Windows if they are not needed then.
You sound like the perfect candidate for Clean Reinstall - Factory OEM Windows 7
which steps are the same for retail.