Unable to load 2nd input language - Language bar crushes explorer.exe

Hi, I deal with the following problem:
I am using the english version of WinXP but I use Greek
as a second input
language.

The last 2 years I had no problem with that at all ( I
used the Left
Alt+Shift key compination to change between input
languages). Last week I
noticed that this key
combination did not work. Now I am able to write only in
English but not in
Greek.
In addition whenever I try to show the language bar
following the Right
clik-->
Toolbars-->Language bar I get explorer.exe crushed.

In my regional settings panel WinXP shows that both input
languages are
working correctly. I tried to uninstall and reinstall the
greek keyboard
support but in vain.

It seems that something is preventing my multi-languge
support from loading
in the shell of explorer.

Any suggestion would be greatful.
TIA - Tasos