Solidworks locks up (sometimes) when opening a drawing file

I am having trouble opening drawings sometimes. I can usuallyopen up a drawing when I first boot up Solidworks, but when I haveonly a couple drawing files and maybe a model file open, I go toopen another drawing file and it locks up. I can move around thedrawing, but the feature design tree stays blank and an I can't goto any other files I have open. I have to control-alt-delete outand start over. When I get back into Solidworks, it gives me anerror message that I don't understand. I am running 2 Gig of RAMand a pentium 4 processor. Does anyone have a solution?SolidworksDrawings And Detailing