File is not showing windows vista

hi
I am panal and i am new to this.
There is a problem that got hang in my work,
I am using vista home edition, loged as administrator
there is a zip file in folder C:/Program Files/A, file name A.zip, contains
a.txt, b.txt....
i deleted a.txt from A.zip file when using vista and created a.txt when
using windows2000
and added to the A.zip file but
when i opens A.zip file from vista, a.txt file is not showing,
copy, move all these things working but the file a.txt is not showing.
i tried all ways that i & the os can do
but no result the file is not showing

please help to solve this problem
thanks in advance