Browsers very slow or failing to connect but other apps ok

[alljam]

I have a bizarre connection issue on my desktop PC; Firefox either takes minutes to connect to a site or fails, Chromeyand IE9 just fail. However Outlook 2010 connects fine as does Norton Internet Security 2012 and Steam. My iphone, ipad & Windows 7 laptop all connect using my wireless network just fine. This hasn't coincided with any major software updates/hardware additions. Initially Firefox would be 'Not responding' more and more until things have got to the stage they are.
System is Windows 7 Home Premium 64 bit. After some googling for advice using the laptop I've scanned using Malwarebytes, Norton & the Windows Malicious Software Removal tool. I've also run the WinSockFix program. None of this has made any difference so I am a bit stumped.
The browsers are not set to 'work offline' and are using the System proxy settings to connect. Does anyone have any suggestions?

 

[Music Guy123]

Well, two things, what hardware are you using, are you using Ethernet directly into the router or a particular card? Secondly and most likely, what security software are you running? I'd suggest using something like microsoft security essentials. It is fast and pretty good. Some other ones really can cause problems, especially using multiple ones. Hope this helps.

Edit: oh and make sure your drivers are up to date!!

 

[alljam]

I have a sky broadband router which I've been using since 2009. The ethernet cable goes directly into it. I've been using Norton Internet security for the past 3 years (2010, 2011 and now 2012 since march this year). I've also checked that the drivers for the Network adaptors are all up to date.

 

[Yamikotai]

Go into cmd. Type:

ipconfig /flushdns

Press enter. See if that helps.

 

[mishra]

what Yamikotai suggested should help. Looks you may have DNS issues.

Restart your router first, then:

ipconfig /release
ipconfig /renew
ipconfig /flushdns
ipconfig /registerdns

This should help. Type each command one by one in "Command prompt" and wait for each command to resolve. Then try:
ping www.google.com
and also
ping 173.194.66.147

...if each of the ping commands will respond within same time period, then all should be fine. If not... do a full system antivirus scan and also Malwarebytes scan.

 

[alljam]

Last night I tried the ipconfig/flushdns fix (running as administrator) but it made no difference. I'll try Mishra's suggestion when I get home tonight.

 

[alljam]

tried the latest fix but has made no difference, virus scan shows up nothing. I have just noticed that my windows 7 office laptop has no problems with any browsers on my home network but my old Vista laptop has the same problem as my desktop PC. Having a look to see what the browser config differences are.

Just deleted Steam off the old Vista laptop and that has made a huge difference - can connect to websites ok now on Firefox and Chrome. Even IE9 as well although it was very slow. I can't get away with deleting Steam off the PC right now (youngest son has about 100Gb of games/saved games and nothing backed up in the last 2 weeks) but there must be something in the Steam setup/configuration that's probably causing the problem.

Rebooted the PC and the browsers are now behaving properly, so Mishra's fix has done the trick - thanks for that and also to everyone else who helped. Applied the fix to the Vista laptop and after a few minutes noticed the difference.