When I boot up my computer, everything looks fine.  When I open a program and
move my cursor into the program's window and click the blue active bar at the
top of the window changes to grey and my computer is vertially locked up.  It
doesn't matter what program, it can be Eudora, or Explorer or anything else.  
The first time this happened I did a CRTL-ALT-DEL in an attempt to reboot my
computer.   The Windows Task Manager window opened.  When I moved my cursor
into that window and clicked, the blue bar at the top turned grey.  When I
clicked a second time, the bar went back to blue.  At that point everything
on my computer works fine.  I close  the Task Manager window and work on my
computer.  I must do this every single time I start Windows.  It doesn't
matter if it is a reboot or a cold boot.  Another symptom -   I have my task
bar hidden.  When I pull my cursor to the bottom the task bar will not come
up.  Once I go through the whole Ctrl-Alt-Del thing the taskbar comes up as
it should.  One last symptom - Once I boot my computer, if I do not touch
anything the screen saver will start in 10 minutes as it should.  Once I do
the Ctrl-Alt-Del thing, even though the computer runs fine, the screen saver
will not run again.       I am using WinXP SP3 now but had the same problem
prior to SP3.