OK, assuming you can boot into Windows 7, search in the menu bar for 'System Repair Disc' then create one.
Next, backup any data you have on your Ubuntu partition (basically open your '/home' folder, press 'Ctrl+ H' to show all your hidden files, then copy across to an external drive.
Next, run Zorin Live and launch GParted - now delete any ext4 partitions and also delete your swap drive.
Next Boot into Windows, run chkdsk (reboot required) then run 'Defrag'.
Next, use your Windows system repair disc so that your mbr is overwritten so that when you boot it boots to Windows - if at any time Windows asks you to do a reboot, do so.
Next put your Zorin disc in and follow my guide here: (Well it looks like someone has deleted my dual-install guide! Will upload later!)
It might be in the pdf tarballed here:
viewtopic.php?f=4&t=5435Even though it is based on Zorin 6, the installation procedure (manual setup) still applies!