Internet Issues using XP

ISP: Optimum Online - Cablevision

I have cable, voice service & internet through this ISP.

My PC was able to access the internet without any issues
until I installed a NetGear router. Upon installation of
the NetGear Router I began having connectivity issues
until I lost my connection completely. At that point, I
disconnected the router and tried to connect directly with
the modem. I can open Internet Explorer but I can't get
any pages to load.

My cable modem reflects that I have activity (indicated by
lights). My ISP tells me that I have a connection and they
are able to ping my IP address. I am able to Ping my IP
Address and get a response. I am able to ping other IP
Addresses and websites. My Ethernet Card shows that it is
enabled and that I have an active connection but I cannot
open any webpages at all.

Troubleshooting that was done:

1. Removed Router and connected the modem directly to the
PC
2. Shut down cable modem and turned back on in addition to
re-booting PC
3. Swapped out Cable running from PC to Modem
4. Confirmed that my TCP/IP properties are set up to
obtain an IP Address
automatically.
5. IPConfig Release/Renew
6. Brought home laptop from work and connected directly to
the cable modem
and had same exact issue as my home PC.

My ISP thinks it's an O/S problem. Has anyone experienced
this issue before?? I am not that technical and have tried
to troubleshoot the best that I can but I guess I am
missing something. Any advice would be GREATLY
appreciated. Thank you!!