We have all been there before.  There is the idea that is flowing from the mind to the screen.  One part to the next part, this feature to that feature and then the computer becomes unresponsive for 5 to 30 seconds, (the longest I time I have experienced because I know I forgot to hit save).  Then the program crashes.  

If you like to copy drawings and parts it would be a great idea to save and load a current drafting standard to all the older files.  Sometimes these older files have some setting that has been removed, or upgraded, and will cause some computer conflict.  
Having all your library models upgraded to the latest version is also a great idea for the same reasons. 

For a repeatable crash I have found these steps to work best.  

1. Quit accessing the command from the same location.  (go to the command manager and pick the command from there.
2. Restart computer, 
3. Start a detailed explanation to tech support.  (by the end of the e-mail, more times than not I come up with a way to keep moving       forward with out having to send the e-mail)   
4. run an rx video capture if I sent the e-mail so I can upload the data to the tech when they respond to the e-mail. 

One assembly I was working on would crash as you would do some routing in a logical step, Every time I would add that fitting to the rout it would crash.  I went and added something else to the rout, saved it, and then tried to add the fitting, and then it worked.

Another thing I have seen is that one computer would be on one service pack and another one was on another.  One guy would crash all the time trying to open a file when his coworker could open it no problem.  This was also the case of the remote computers where it was a crap shoot if you would get the same version of SolidWorks that you did the day before.  One computer had sp1 another sp3 and there was one that had sp4 i think. That was why one morning I showed up to work and could not open the assembly that I was working on the day before. 
    
What kind of Repeatable crashes have you experienced and what did you do to get it resolved?