Windows 7 cannot start
Some systems are known to have issues with the windows installation if a 64bit ubuntu is installed alongside. Using a 32 bit version produces no problem. You can try the boot-repair iso to fix the dual boot screens.
https://help.ubuntu.com/community/Boot-Repair
Boot repair can fix most of the common problems with grub.
This sounds like a Windows Loader problem. You should try to do Windows Recovery via the installation media.
More info on recovery can be found on Microsoft web site.
I would start with startup repair and see if it works first.