short term freezing

My computer has worked normaly for months. In the last few days it has started freezing up for between a few seconds and a few minutes. Durring the time things are frozen on the screen the led indicates the HD is opperating. The first thing that comes to mind is heat, the longer the thing is on the worse it gets. The CPU ( Duron 950) temp is OK 107f highest I have seen. The primary HD is a great deal hotter then the slave, both Maxtor ( is the temp related to the use?) I'm using business programs, nothing to demanding. Any ideas?