ipconfig and networking problem

I have been having all kinds of problems getting my desktop and laptop to network. I use Win XP home on both have a satellite broadband connection and a Netgear router. I have run AVG and nunerous spyware and adware checks and all clean.
The frustrating part is it will work sometimes for no apparent reason and then stop recognizing each other for no reason also. Sometimes one will see the files on the other and other times the other one will, and sometimes neither will. It seems to have no rhyme or reason.
I just ran ipconfig on my desktop and it seems to operate properly, but the laptop says it is not recognized as a program or batch file, so I can't run a release or renew on it.
Does anyone have any ideas? I'm sure if I wait awhile it'll change but I can't figure out why or how to make it.
I unchecked everything in both my startup menus in msconfig yesterday, including disabling the firewall and AVG. Lo and behold when I rebooted both computers it worked just fine, so I thought I'd start adding things back one at a time and see what made it not work. I first added AVG to both rebooted and it didn't work again, so I disabled both again thinking I had it solved and would just use a different virus scanner but when I rebooted and it didn't work again. I am going nutz. Any ideas.

 

If you have Norton Antivirus may want to check on their site.
Microsoft also has something about it.

Damit - I don't have file with me or could send exact link.
Norton sometimes - not always - changes a registry key that intermittently screws up communications. It's a 1 time fix.

It drove me nuts until I ran it down.
Won't be back home until Monday. Will post it then. If in a hurry - n you have Norton-- search their site - also mircosofts support- they both mention it.