Not connecting to Internet

Hi,
I got Charter cable internet services and it went well for 2 weeks and suddenly it stopped working. I have Linksys wireless router connected to the cable modem and it was working fine.

Now I am not able to connect to internet either through wireless or wired. I tried with Charter guys and they gave up. They tried all options like switch off modem, reboot the system, deleted the network driver and re-install apart from renewing the IP etc but still the laptop is picking DHCP IP address (192.168.100.1). The charter guys say it may be some software problem.

I am not a systems guy, so don’t know what more details to write. If any more details required to resolve the problem, please drop me a mail.

thanks,
Bhaskar