Problem with Routing Table

We own an Inspiron E1505, which is about 6 months old.  Recently, an error message has periodically popped up which reads (through the Dell Network Repair Wizard) "We have detected a problem with the routing table on your computer and successfully repaired it." Then when I attempt to access the internet, another message reads "We have detected a problem in your service provider's network.  You should contact them for help with this problem." The green checkmark icon turns to a red X and I am forced to restart the computer in order to stop the problem. This is an intermittent problem which doesn't appear to have any "rhyme or reason" behind it.  It makes it difficult to analyze and solve the problem because it's inconsistent. Most of the time, we are able to access the internet with success.

We have a desktop, linked to our Linksys router, and my husband uses his laptop from our home network.  Both of the computers have no problem with internet access, and we have confirmed with our internet provider and the linksys technician that our internet service and router are in working order.

I have concluded that the problem lies somewhere within this computer and would like to resolve the (very annoying) problem.  We have disabled our firewall programs, changed our wireless signal so as to not interfere with any neighbor's networks, and changed our cordless phone in order to minimize interference. We even consulted a family member, who is a tech guru, and he can't seem to solve the problem either.  His thought is that there is interference from neighboring networks, but it is not a problem with my husband's laptop.  Any recommendations?