I did fresh installs of Ubuntu 12.04 on all my computers yesterday and one of them just doesn't seem to like 12.04. Let's start with the symptoms:
I initially tried installing through a USB flash with the desktop amd64 version. Since it had worked on all other (5) computers, I believe the USB flash drive was ok. However the computer seemed to be stuck after the Ubuntu GUI came up (bar on the top, pinkish background) but before the screen prompting to Try or Install. When the screen came up, the mouse was moving exceptionally slowly, i.e. it responded 2-3 seconds after I had moved it. After a few minutes, I could move the mouse with normal speed, but could not click anything. The Try/Install window never came up. The same thing had happened a few days ago when I had tried to install Ubuntu 12.04 Beta 2 on the same computer, but when the Try/Install screen kept failing to come up, I gave up.
I assumed it was a problem with the desktop installer, so I tried the alternative installer, which worked fine. But then, the same (or possibly a similar) problem appears on the login screen: the mouse moves very slowly in the first few minutes, then it moves normally, I cannot click anything (for example the buttons on the top right), and I cannot type in my password to login or select the guest session.
So I am stuck at the login screen. I did not encounter any problems on my other computers, so here are some specs of this one:
CPU: Intel i7 980x extreme edition, Motherboard: Asus Rampage III extreme, RAM: 6GB, GPUs: 2x NVidia GTX 580 in SLI, HDD: Western digital 1TB green power (20GB for root (/), 6GB for swap, all the rest for /home)
I should also note that this PC ran 11.10 flawlessly until yesterday, when I attempted to install 12.04. I tried installing 11.10 after I failed with 12.04 and it worked again, so its definitely something related to 12.04.
Unfortunately, due to the nature of the problem, I don't know how to provide any logs, but if there is some way let me know.