internet explorer

customer just added dsl to their system. restarted the machine and everything was fine. about 2 minutes later the internet explorer shut down and won’t guve access. they still have all they messangers running but no explorer. they are running winxp with service pack 2 installed on a dell demension. everything is up to date just no internet explorer. tried the same disk and modem on another computer that they have and it works any help here?