Network Connection IN & OUT

System: Dell 4400
OS: WinXP Pro w/ SR3
NIC: Linksys 10/100

Issue: I had this system at my work desk connected to the LAN with a CAT5 line... working just fine. Moved it to the area where it was to go and now the connection comes and goes (in seconds).

Tried the following:
1. Thought the line might be bad, connected a laptop to the line and it worked fine.

2. Moved the NIC card to another slot on the Dell system, no change.

3. Turned the hub (that this line goes through) off - on, no change.

Cannot think of why it is doing this. Cannot see what is causing the problem (ie - a program on the system) as it was working in a different location but on the same LAN.

Any thoughts?

tia (thanks in advance)
bgunn