No graphics output

I have been having very bad lag with the nvidia 290 driver, installed through the propietry driver program. I have posted a question related to this earlier, and actionparsnip suggested running:
sudo nvdidia-xconfig
I ran this, but on a reboot the lag was still there, so, I tried installing the nvidia driver found on their website, instead of the one in propietry drivers(others have had similar problems and this has worked for them). However when I ran the install file, it said something like:
you are already running x server, I thought this might be because I still had the propietry nvidia 290 driver installed, so I removed it, I then restarted, to make sure that it had properly been removed, and I got the grub boot selector displaying fine, then I had the startup loading screen but it was just purple, with no loading bar (this was like this while I had the 290 driver, however, before then I used to just get an "input signal out of range" error from my monitor, until the login screen appeared.), Then, after the purple screen, the monitor told me it was "going to sleep", I turned the monitor on and off again, and it told me that it had "no input signal". I am now having to select windows at the grub bootloader, as, as far as I can see, I am completely locked out of ubuntu. Is there anything I can do to fix it.