for some reason, after installation of Ubuntu 11.04 on my HP Compaq 6715b, I attempted to login and in the middle of the process, the computer halts and noting happens afterwards. I'm forced to start the computer in safe mode. Apparently, the new desktop features are unable to load.
For some features like Unity 3D you need better hardware, otherwise it will fallback to Unity 2D, but you can also run classic gnome desktop, which is not so cpu and gpu power hungry.
If that happened just after install maybe you will need to add or enable some drivers for your hardware, many times I saw that same hardware under different drivers act differently, under one driver same hardware not work under unity3D but when i find better driver it works!
Under safe mode it is normal that some functions are reduced, or not loaded. For example in real recovery mode there is not desktop,just text mode so:
Investigate and activate graphical card perhaps proprietary ,for your laptop.*depends what u have inside as Graphic Card,or integrated card...
that is mostly normal,not to all,but to newer hardware ,yes.
Under Ubuntu you can find variety of different drivers for same hardware, not like under Windows.
without login ,you can not proceed. check,login user name and password that is correct ones. then check that is not activated some other type of keyboard or language,as that can lead that u press correct letters,but lead that will be entered some other ones. And also disconnect all from urs machine,all usb periferia..and connect it again ,as that can cause shorter or longer freeze(but that many times just look like that..) if that not solve ur problem then,reboot and run recovery options from boot menu or from liveCD.