Did you boot it and run "startup repair"
three times ?
(it can only fix one thing per pass and there are possibly several missing parts to a failing boot)
If, after that, the OS is still not booting, boot the USB stick again, but instead of "startup repair", use "command prompt" to run a
chkdsk /r against your OS partition. (it takes a while).
Then try the startup repair sequence(s) again.