I used AOEMI when I upgraded a Windows 7 laptop for someone. If it was me, I'd assume I did something to the boot partition or that the drive itself is bad. You can get an SSD for around $50 (try Newegg or Amazon) if you just want something to make the computer usable again. If you saved the old HDD and/or do backups to it, have you tried placing it back in to see if it's the connector?