System Locks up after kdevelop install

[Ross Drinen <drinenvr@yahoo.com>]

I installed debian/gnu linux for the first time a couple of months
ago for the first time. (I had been a redhat user formerly.  I got
kde, apache2, ftp server, mail etc working and all was well.  Then I
decided to install kdevelop and its recommended packages.  After
that, the system started locking up periodically.  I can operate,
sometimes for an hour, sometimes for a day, but eventually it just
locks up, often (but not always) upon opening a new window, or when
resizing a window.  

By "lock up"  I mean the mouse will move, but has no effect on any
windows, often a window will be outlined, but its contents will not
be painted.  No keyboard action has any effect, including switching
to a virtual console.   And ftp, samba etc connections from other
systems do not respond.  Sometimes it will get a bit sluggish briefly
before locking up, sometimes it's without warning.

I have deinstalled kdevelop and all that went on with it, to no
avail.  I've used top to try to see if I can find memory leak
indicated etc, but see none.  I'm at the point of reinstalling the
operating system from scratch, then staying away from kdevelop.

Help!  How would I go about diagnosing this?  What measures shy of
total reinstall would anyone suggest?  

Thanks for any ideas.  
Ross