Computer freezes

How can I repair a networking problem that is causing compac presario running WinXP home Ver. that stops responding shortly after internet conn. is made? Onboard realtek 8139/810 fam fast ethernet is being used. I have also tried a netgear fa312 pci nic which worked for a short time then soon failed. Using Roadrunner cable modem with Linksys router Model NR041 that has updated firmware.I am running 2 computers- 1 with win xp proThat has same onboard NIC(working fine)And the freezing compac with XP Home.Ran IPconfig /all and the only difference is the compac has wins Proxy enabled. I tried the winsock repair utility which did not work. Help Please?