Disclaimer: I don't know what I'm doing, so let's keep it simple!
Right: problem is that I can't access some websites, whilst others work fine. Specifically nationalrail.com and prototypegame.com are two unrelated sites that don't load. Status is either "waiting for ...", or "done", while the tab says "connecting". I can ping both of these sites successfully in the cmd box, I can also ping my default gateway. Sites I cannot ping (request timed out) or access include thetrainline.com and microsoft.com!
I'm running Windows 7 Home Premium 64-bit, IE8 and Firefox 3.6. The problem is the same with both browsers.
Things I've tried (in roughly this order):
Running AVG and AdAware scans
Restarting my modem/router
Restarting my computer (multiple times!)
Disabling Windows Firewall
Uninstalling AVG and AdAware
Running CCleaner to get rid of all temporary files, cookies etc.
Cleaning up the registry with CCleaner
Renewing IP address
Disabling TCP Windows scaling
Swapping my ADSL filter
Pulling my hair out
If anybody can shed any light on this, you may save my sanity...
If using a public DNS, all external host names should be resolved properly. Your answer to eibgrad proves that something is wrong at your end. It definitely isn't normal to sometimes get IP address 127.0.0.1 when pinging any host other than localhost.
Sometimes anti-virus and anti-malware software (and maybe even malware itself) will muck w/ your hosts file and map domain names to 127.0.0.1. That prevents you from accessing those websites since 127.0.0.1 is your machine! So obviously it can't load.
I've reset my router and gone though the auto-setup procedure and the problem's still there. I really don't know what I'm doing when it comes to playing with router settings so do you have any ideas for what to change?
My ISP is AOL and I have a cheap D-link modem/router that came free with the internet. The only thing I've tried is unticking the Enable Firewall box, but the problem's the same.