LAN connection problems

I am having problems with the internet LAN connection with my desktop PC since changing my ISP from AOL to Post Office a month ago. They supply a Zyxel_5664 wireless router.

The problem is the internet connection keeps dropping on the LAN connection. Wi-fi works fine. If I ping during these breaks in connection - I get no response (0/4) from a website but full response ie 4/4 if I ping the router.

I have tried using my netbook to connect to the internet via LAN (and wireless switched off) and it works fine - so it must be a problem with my desktop PC.

When I changed to Post Office I installed Kaspersky and Netintelligence - but I had so many problems with NI blocking stuff so uninstalled it. I think it might be something to do with that. However I did the same thing with the netbook and it works fine. I am currently running Microsoft Security Essentials and Windows Firewall.

Have you used the removal tool for Kaspersky as AV never just uninstalls, you need to use the removal tool to clear out the bits left behind.

thanks I'll give it a go. I don't hold out a lot of hope as when I ran it it said nothing detected on computer, but I'll see what happens now. Thanks.