|Just because a hard drive can be read okay when connected to a USB adapter, it doesn't necessarily mean it will boot in to Windows okay when you put it back in your computer.|
The Windows installation or Windows startup configuration on the drive could be messed up. If it's just the startup configuration that's messed up, you can usually fix that by booting from a Windows 7 System Repair Disc and choosing "Startup Repair".
You are supposed to make this repair disc with the utility that's built in to Windows when your laptop was working okay. If you didn't make one, ask a friend who has Windows 7 to make one for you.