Try installing the 32-bit version of Lightroom from the latest 4.4 update ZIP, by running SETUP32.exe directly. If it is some sort of 64-bit driver problem, the 32-bit version might work.
Are all the photos importing but when it starts to render previews phase it locks, or is it still in the middle of the initial Import step?
Can you import the photos in smaller batches—or one-at-a-time and have things work?
To gain control, are you ending task on it, or rebooting? How long have you waited for it to start responding?