Bizarre Internet problem

[Squark]

At the moment, my computer is misbehaving (again). This time, a lot of programs can't access the internet. The connection is there (I'm using the machine in question), but Steam, The Sims 3, Spore, and even my Firewall have problems. My OS is Windows Vista 64-bit, by the way.

-Steam: The Steam store and community pages come are unable to connect to the server. Strangely, I still get messages saying the GITP Steam group is doing something. Fortunately, my steam games page is accessible.

-The Sims 3: The Welcome page on the Launcher cannot connect, and every download I've tried recieves an error message. Strangely, I'm still able to patch the game.

-Spore: Haven't played in ages, but Spore seems to be unable to connect to the internet anymore.

-CA Security Center- It can't update it's virus protection. Since this is also having problems, I've ruled out the Firewall from this as the culprit (plus, I tried disabling the firewall. No go).


So, If it's not the firewall, does anyone have any idea what it could be?

[Obrysii]

Reboot the computer. Might be having issues with your network drivers.

[Squark]

Sorry, I should have specified- This has been a long-term problem- I've been having these issues for months. So restarting has been tried (and failed).


That being said, I could check my network drivers... Where do I find them?

[Obrysii]

Device manager. Might need to update the driver - once you know the make and model of your motherboard, go to the manufacturer's website to download the appropriate driver.