Primarily, make sure the slowdown isn't resource related, i.e PC with 2.8Ghz and laptop with P233Mhz etc.
(I am assuming you are running 2 100Mb/s cards (as you never specified your hardware))
If you, have them connected through a 100Mb hub/switch u need 100Mbs capable cables (Cat 5 and above)
If you have 100base-t connection between the PC and switch, then ideally you need to have the same the other side too. If not the laptop could be "autosensing the connection speed" and if you're running say a Cat4 cable from the laptop to the hub/switch then you could suffer slowdown/collisions.
Also look for firewall rules regarding you LAN environment on both PC's. They should both "trust" eachother.
Hope this helps a little.
ok here is more info... i was in a hurry this morning =) had to do the old work thing.
laptop is a 2.4 ghz (XP Home)with 512mb memory with 10/100 mb lan card
home pc is 1.0ghz (XP Pro) with 512 mem and 10/100 mb lan card
they are connect via cross over cable sharing the same workgroup (hopefully i said that right) via tcpip.
I do internet sharing from my cable modem. it is directly connect to home pc. I use a netproxy program that enables me to do this. the laptop gets an ok connection... nothing like the home pc. oh yeah... and dont use a firewall.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS