Can't copy paste files !!!!!

I don't know why....Last night i did upgrading my IE5 to
IE6 on my win2000 pro box. After restart, I can't copy
paste my files (!).
I logged on with administrator account, still can't copy
paste. The wierd thing is :
# I can copy paste from another computer.
The win2000 pro box has a shared folder and I connected
into it from another computer with my account. And I do
can copy paste !
# I can copy paste with using command prompt.

But everytime I use the right click or by click edit copy-
paste...nothing happen. The file(s) or folder(s)not copied.
"The additional wierd things" :
- I can make a file and or folder by right clicking cursor
and choose NEW --> whatever.
- I still can change file content such as Word document.

So, I think it is clear that it has nothing to do with the
security or read-write previlleges thing.
So...WHAT HAPPEN ??? AND HOW TO FIX IT ???


cheers,

dizzy