urgent help needed Zorin not booting

Hi to all you knowledgeable people out there, i am very much a newbie to Ubuntu or any form of Linux to be honest. I have installed Zorin on to my system and it look quite good, i have been using tweak to update the system and it was all going fine until i needed to reboot to finish the updates. on reboot i get the GRUB menu for 1 second then it tries to boot, i then get a bar going across the bottom of the screen, it is a dark blue bar with a lighter blue bar chasing it and then a white bar chasing that. the screen then goes blank and i am sitting with what looks like a cursor flashing in the top corner of the screen and i can do nothing. any suggestions?

Like i said i am completely new to Ubuntu so please be gentle with me and if you say for me to do something please spell it out like i am an idiot because when it comes to this i am.

Many thanks

BD

Thanks for the quick reply, but i have it solved now. I re-installed the whole system again lol.

if Ubuntu Tweak is not on the list of main 'trusted' repositories why was it part of the original installation from the live disk? (that is a rhetorical question and i am not looking for an answer).

I do have another question though, before i downloaded it, i read reviews that it is possible to install all of the features that are in the other versions of Zorin, is this true? and what are those features, the Zorin website does not have a comparison list so if you do pay for it you don't know what you are getting.

Thanks again

BD