Down loaded SL 5.8, created DVD's and updated test system not a fresh install.
The only causality is LibreOffice 3.5.
When you open a LibreOffice file and try to edit a file the key board is 
disconnected.  Once you type to  a LOffice 3.5 document,  display gets dumb, 
and it eventually asks you to terminate the program.  Did SL 5.8 install a 
new KDE for me?

Everything else appears to work - 

I noticed that I now have KDE 4 as a desktop.

Tried to install a new version of LibreOffice 3.6 to see if it would behave 
differently.   KDE complains that it cannot launch /usr/bin/libreOffice3.6 
and quits.
Looked on Net and there is so much noise about KDE and this subject - Had to 
quit but never found a solution but KDE developer closed bug report.

Is there a way to regress back to SL5.7 from SL 5.8 , that was on this system?

Fortunately this is only one system and not many.

Thanks
Larry Linder