I even went to the trouble of installing it again in a diferent corner of my HDD. And guess what, that instalation works perfectly while mine freezes just when the logo screen is suposed to pop up.
But no need now, I managed to get it to work. I pressed "Restore last configuration" (Or something equivalent, translated from portuguese) and it booted. Not sure if it'll work next time I turn on the computer, but still.
You should go about backing up all your necessary files because if this keeps happening then there is likely to be a serious issue that might become irreparable. You should also see about diagnosing the problem so that you may be able to stand a better chance of repairing it should it recur. A good start would be to take a look at the Event Viewer, whilst saving the logs for future reference. You should also run your resident security programs as well as an online scan, such as Trend Micro's Housecall as there could be a malware problem.