RHEL 4 - Screen saver problem

[Florez, Nestor]

For the last year, I have had my screen saver set up to run after 5 minutes when not in used
and all I had to do is click the mouse button and I was back on my computer ready to do stuff.

About 2 weeks ago, I started to have the problem that when the screen saver came on and I 
left click the mouse button, the computer is not coming back.  It stays in screen saver mode.

That only way I can go back to have access my computer is to reboot the computer.

Any ideas what can be causing the screen saver to lock to the point that I have to reboot?

Thanks,

Néstor :-)