hmm .Sprint Q, I will guess it's when a bunch of txt start flowing in or are not deleted. Mine would lock and freeze if i didnt delete old ones in a timely manner or recieved a flood of 'em.
..or the Q's out of memory
try updating your vision profile, Sprint web has sucked lately for many here. I normaly have to poer cycle 15+ times a day to have any kind of data services.
Are the lock ups and freezing just limited to web use?