I'm running Kubuntu 13.10, my computer's graphics card is Nvidia GT 520. I tried to fix that Plymouth's problem with proprietary graphics driver using an old script I found on the internet (it was coded for Natty, now that I think about it I shouldn't have done it). I ran that script and rebooted my computer.

First incorrect behaviour I noticed was that Plymouth only displayed its text splash only on 1/4th of the screen, though when I pressed Esc key the logs were displaying correctly.

Main problem appeared when I logged in. All my desktop's windows lack menu bar, can't be closed with Alt-F4, and they don't appear on the task bar.

I tried fixing it by reinstalling GRUB a few times, purging /etc/grub.d and /boot/grub, but only the text splash issue was fixed. How can I fix that?