How this happend ???Duplicated record

[fule12]

hi all,
I have DB on server like Purch_be(back-end) and on workstation
Purch_fe(front-end).In Table Order field OrderID is set like PK. Same how 1
time in week or in 2 week if I run Query Find duplicate order there is 1 -
5
record duplicated. Is not only OrderID complete record is duplicated. like
twins.
So if delete first duplicated record it will delete twin order as well and
in all field for that record will be Delete#.Now when i delete all
duplicate
record and if i try to open Order table is open to me pop up window with
message "Record is deleted". So i convert and repair Purch_be.After i can
open table order and top record are one what i deleted where orderId field
is empty but two field ( orderNo and Order) are populated with
#########.Now
i delete this record and i go to design view and OrderID don't have PK
anymore!!!!
On Server I didn't install Office and all workstation use Access 2000(sr-1)
or Access 2000(sr-2).

Please Help !!
Thanks Fule