Clearing your DNS cache on a PC
Launching a new site? waiting to see it come up live from the old placeholder version? Then you may need to clear your DNS cache.
When your new site gets launched a setting for your domain name is changed, that setting is for the nameserver configuration. The nameservers tell other computers where to look to find out who hosts your site.
When these change it can take time for those settings to be recognized/propagated to other servers and internet providers. Most internet providers have their own DNS servers that perform these lookups. Usually these DNS servers have a cache so they can provide faster lookups for their customers. This cache holds old data and can take some time to clear out so you get the new record.
Besides cache, it can also take some time for the domain registrar to update the setting internally on their own server configurations.
Besides the usual where there is a cache with your internet provider and a time lag with the registrar for updates your individual computer holds a cache of these queries as well.
To clear it out we need to run some commands from the command line.
From newer computers ( Win vista and up ) you will need to go to the Start Menu -> All Programs -> Accessories
Right click on the "Command Prompt" option and select "Run as Administrator". That step is important to do so you can get a command line with access to be able to clear the cache.
If you are on older windows you may be an administrator already, just go to Start Menu -> Run and type cmd then hit enter ( you can access run through a hotkey holding down the windows key then hitting R ).
When you get the command prompt up, type
that command will clear your dns cache.
Then make sure to clear your browser cache and then close/reopen it ( browsers can also have an internal dns cache that will only clear on close/reopen ).