Yoshi2889,
Would you start a new post in the questions section related to the issue you are meeting with ? You could describe fully your hardware (lshw, lspci... ) and bring back the contents of your dmesg and syslog log file from just after boot... If you don't mind trying to get into it, of course.
I already know what causes it
It's a combination of X, DRM, lightdm and Plymouth.
What happens, is that Plymouth takes DRM control as one of the first steps in boot. But due to the fast nature of SSDs, Plymouth doesn't get to finish its task. Now X wants the control over DRM, before Plymouth has finished its task (so Plymouth still holds the control over the DRM). DRM gets all confused and fed up, then "attempts" to pass over control to X, which fails as Plymouth is still running and holding control. With DRM confused, X thinks it has control, which it has not, as DRM did pass a "Hey you have control now" message in its confusion. With this all, lightdm crashes and therefore it gets stuck on a black screen with a cursor (as X has kind of started) or Low Graphics Mode as DRM gives invalid information about the graphics card along in its confusion.
In layman's terms, the boot process has finished, but the boot splash screen still has to be shown. Everything's going too fast for certain processes.
Good news is that there are people working on this issue, and I hope it'll be solved in 13.04 final.
About the random freezes, nobody knows. Probably worth it to install Elementary again and dump some logs in the teams hands.
