I have Microsofts DOS client software installed. Isn that a packet driver?
No, those are NDIS2 or NDIS3 drivers. The NDIS drivers you load via NET START may be adapted to work with Packet Driver clients using the shareware shims DIS_PKT.COM (for NDIS2) or NDIS3PKT (for NDIS3), but I haven’t tried DIS_PKT.COM, and NDIS3PKT doesn’t seem to work well with MercNet. It is probably better to install true packet drivers.