Sometimes when I attempt to access a URL from my browser, it fails to load, however when I look up the IP for the domain name using my router's whois tool and type it into the address bar, I can access the website. Other software that accesses the internet sometimes works as well, such as Steam. I have found a temporary fix: uninstalling my NIC drivers, rebooting, and allowing my drivers to reinstall seems to help, at least until I reboot again. The problem and the fix are reproducible. Salient facts: Win7 pro SP1, Comodo firewall, linksys router that's a few years old, connecting via ethernet. -------Fix attempts: * Router Powercycle * Modem Powercycle * connect directly to modem * turn off firewall * try different browsers * try Google's free DNS * Checked in with ISP to make sure their DNS wasn't having problems * make sure proxies aren't running - tor isn't running, proxy settings are clear in browsers * update NIC driver * clear hosts file in /system32/drivers/etc * make sure UAC is activated * scan for virii/malware using avira, malwarebytes, superantispyware, hijackthis, ckscanner * at command prompt, run: netsh int ip reset **then** netsh winsock reset **then** ipconfig /flushdns * Fix registry errors via glary utilities * updated Java and Flash and cleared out older versions -------Other diagnostic symptoms when unable to resolve host names: * nslookup seems to work (this is strange; why would nslookup work, but hostname resolution fail elsewhere?) * pinging a hostname from console does not work * Comodo doesn't show unusual activity, as best as I can tell * networkminer doesn't show unusual activity, as best as I can tell * router can ping host names * Can't see other network computers on windows network * Steam connects, sometimes after asking for a retry * Avira fails to update when prompted --------Other diagnostics: * Web browsing works proplerly from an Ubuntu 10.10 live CD * One other computer (also Win7) on the same network had a similar problem a little while ago - I wasn't using it, but it apparently gave an error a couple of times along the lines of saying that network drivers weren't installed or weren't installed properly, but rebooting fixed the problem and there were no notifiers of drivers for new hardware beign reinstalled. This error hasn't happened recently, and I'm not sure how reproducible the problem is. * Other devices, such as laptops and smartphones, don't seem to have trouble connecting.