Security Breach

Machine: NT 4.0 Server SP5
Network Components: NIC and Netgear Gateway Router RT311

Recently had high speed cable modem service installed.

After 2 weeks started seeing 2 W: drives in my Windows explorer. Pressing F5 (refresh) in explorer would clear the “W:” drives

First time I discovered this, opened Outlook Express and noticed that my whole “Contacts” list had disappeared.

Anyone have any ideas what’s going on?