My Computer "Access is denied"

WinXP Media Center Edition v. 5.1 SP2

I'm trying to fix/figure out why I get an "access is denied" error

message when I open:

Start/My Computer

If I double-click c: d: or e: drives I get a message saying "Access is

denied".

BUT... if I open Windows Explorer and click on these drives I have

full access to them.

Would anyone know why I have these two contradictary results and what

I can do to fix the error messages when I try to access the drives

from My Computer?

TIA