In all honesty, it could be either...though I would guess it's a network (or networking configuration) issue.
I would do a basic systems check (hardware, start up programs, etc). If I didn't see anything untoward, then I would try booting with just basic network support. If it loads quickly it's a software/driver issue. If its the same, continue testing. Take a close look at your network card configuration, the protocols you are loading etc.
Get rid of anything you don't need. If your networking configuration is basic, it may be worth the effort to strip it out and set it up again in case something has become corrupted, etc.
If you don't see a problem there, set up a workstation to packet sniff the network. Start capturing packets and then power on the Dell 2000. Don't touch any keys or anything on it (other than entering a password). Take a look at the communications going on, the kind of packets sent, the time on each packet, etc. Watch for errors, rebroadcasts, drops, etc. A great site to take a look at for this sort of thing is www.packet-level.com
Good luck....hope this helps!