All network computers run ok, except an XP laptop.

I have an established network that works great, but my
laptop has serious difficulties with it. It sporatically
takes several minutes to access server folders and
applications and almost always has problems printing.
Especially on our plotter - the transmission slows to a
crawl (less than .01% capacity) then times out "Document
failed to print". When I connect directly to the plotter
it works great. No other computers on my network have any
difficulty. This laptop has XPpro with no SP because SP1
caused serious problems and was removed. Other than this
network thing, the laptop runs great.
Any help here would save me countless hours of frustration.
Thanks.