internet security and network problem?

hello.I have gigabyte chipset which have built in marvell youkon lan card. i formated my whole computer.i again installed window xp sp2.my computer was running fine.but when i install kerpersky internet security and restart my system.my slowed down too much but the lan card is not working.after 10 min it detects the network cable.and when i try to connect internet i says somthing about registration to the network.i triend uninstalling the internet security and it is having problem again.i formated it and used another internet security still same problem.please help me