Ports are blocked and don't know why.

[Jaguar_XJ220]

OK, so I have a Linksys router and have never had any problems with it. I have have always been able to open all the ports i need and been able to host on any game etc. The other day I was trying to host a game of COD4 on my XBOX and some people were unable to join. I didn't think much of it till I tried to play a PC game that I always host with no problems and no one could join. I disabled windows firewall, triple-checked my router settings and even disconnected the router and did a direct connection with no luck. The ONLY thing that changed in the time before this happened was I installed new drivers for my nVidia video card and when I uninstalled the old drivers Windows XP asked me to re-activate it since my hardware changed or something. So I activated Windows XP with no problems and that's around the time this problem started but I don't know if it's related. I don't think it's a router issue because I never changed those settings and the problem still persisted even with a direct connect but is it even possible for software on my PC to effect my connection on XBOX Live? I don't have any anti-virus or 3rd party firewall programs either. If anyone has any suggestions for me please let me know. Thanks in advance.

[mikeL]

It is odd that Windows asked to re-activate on a driver update, because your hardware never changed, you just updated to newer drivers, was there anything wrong with the old drivers.

I would run the usual spyware / malware programs, scan for viruses, if all checks out OK, do a system restore to before the nVidia driver install.

[Jaguar_XJ220]

The reason it asked for a re-activate is because the drivers weren't working properly and nVidia said to uninstall the old ones first. After uninstalling the old ones I basically had no display driver so that's what made it think the hardware changed. I tried both ad-aware and Malware Bytes and ran Registry Mechanic to no avail. I even called my ISP today to make sure it wasn't them and they said they aren't blocking any ports, so I really don't know what to do next. System restore isn't really an option because I have it disabled.