Kali keeps freezing

Ok so I installed kali (tried both x64 and x32, using x32 right now) on my harddrive.
but the problem is, for some reason sometimes when I use the browser (chrome /iceweasel*)
the system freezes, it starts with the browser itself not responding (while I can still make those blue squeres on desktop if i click&drag)
and then If I try to open the "start menu" everything else freezes but the mouse.
I tried leaving it overnight but when it kept being frozen after checking it in the morning.

any suggestions?