Why Solidworks crashes so much?
What do you mean by that? I never had a single SW crash in the past two years? What are you doing and what version (SP) do you use, what hardware do you have? Is your OS properly maintained and updated, drivers?
The PC spec on your profile suggests an acceptable configuration that should work well. SW does prefer an adequate GPU - either nvidia Quadro FX or Ati Pro, still, the application is not crashing for no good reason. Check with SolidWorks Rx what might be wrong if the problem is with SW, it will tell you.
I run a SW 2011 sp4 on a cheap (600 euro) laptop when away, with very few crashes, and never causing more than a few seconds of loss. Check your settings, clean up your discs, check swapfile (XP). If your graphic card is up to specs, you may have power supply incidents,