Dell Studio HD Seizes Up

(I mistakenly posted this under Windows 8 before, apologies.)

Recently my Studio crashed while booting, and ever since it tends to sporadically seize up.

It doesn't quite "freeze" per se, I can for instance still type in a website in my browser but it then gets stuck "waiting for cache".

I've been keeping my Resource Monitor open, I've taken a screenshot of the activity.

The right half of the graph shows my HD when it's busy but in normal condition. The left half shows when it freezes up. The blue line stands for "Highest active time" in percentage, and the green for HD I/O in Kb/sec. If I am correct, the HD is for some reason extremely busy while seizing up, while traffic is a bare minimum. 

Does anyone know if this is a hardware related problem?
I don't see any problems with software. What could cause this?

Thanks in advance.