Internet Connection Issues

I have a XPS8300 which was purchased less than 2 weeks ago. Had IE connection as of this past Sunday but tried to get on yesterday and kept getting the message if "unable to connect" message from IE. Tried all the internal diagnosis steps for internet problems but they came up as no problem detected. I contacted Dell Support and worked with one of their techs for 3 hours and could not resolve the issue. They are going to send out the disks for me to re-install on my machine. I am not sure this will correct the problem. I have a cable modem that is connect to my router and then wired back to the desktop. My tablet and netbook both worked and I was able to connect to IE on both (wireless) so I know that the cable modem and the router are working. I tried switching cables and also tried to use my computer on wireless. I did have some connectivity in the beginning when I restarted the computer, the accuweather display came up with my location time and temperature but when I tried to open IE it still gave me the no connection message. I also checked the lower right icon and at times it should it was connected but still no IE. I did notice that the icon would sometimes change from the wired to wireless symbol by itself and change from connected to not connected. Tried to go back to an earlier service point and restore as well as restore the computer to the default programs, neither would take care of this problem. The amber light always blinked the the network cable location. I tried disabling each of the connections as well with negative results. Has anyone else run into a similar issue and if so, how was it resolved?