DNS stands as for Domain Name Server - a server (literally serving your requests) that converts the long and wordy web addresses you type into a browser into shorter, machine-decodable strings of numbers called IP (for Internet Protocol) addresses. It's just like looking up a telephone number by doing a name search. And it's done for you everytime you go to a web address (like http://gtveloce.com/ or whatever).
Now sometimes your local DNS 'phonebook' is down or just not up to date (it can be a day or more out of date). So when you search for a website it just doesn't appear onscreen, even when you 'know' it's there. Perhaps you even put it there. That's dodgy DNS for you. So you may wish to bypass your local DNS instead... but how do you do that?
Well you can simply replace your DNS server record in Windows (or any other operating system). It's safe and easy and completely reversible, just remember to write down your current settings (if any), just in case you need to revert.
There are usually just 2 alternative DNS address settings and your operating system tries one firstly and if it times out it tries the next. Sometimes your ISP (or Internet Service Provider) pushes the settings out to you automagically and other times they ask you (or some software) to do it instead. You may need to reboot after changing the settings, too, but only if it doesn't seem to work straight up.
Here are the instructions (for Windows XP, but Windows in general will be similar).
start->control panel->network connections->local area connection (NOT internet settings - well not usually, anyway - trust me)
->click on 'properties' and a box opens
->click on (to highlight) Internet Protocol (TCP/IP) -> and then click the 'properties' button underneath (another box opens)
->change from 'obtain DNS server address automatically' to 'use the following DNS server addresses'. The DNS server addresses may already be there, if so write them down just in case you want to roll back
->Pick some DNS server addresses from the list below (start with the closest geographic ones) and see what happens. Save all the way back, see if it works in your browser or ping or tracert in a command window (if you don't know how to do that just ignore it) to confirm - and reboot if necessary to make sure the settings have loaded. If it works, great. If not, try a different set of numbers.
Yes, it's tedious, but so is waiting for your ISP to refresh their DNS....
Here are some apparently free public DNS servers you can use (no guarantees, not necessarily tested by me and may have even disappeared - if so, try another)
Public Aussie DNS Server: 188.8.131.52 (I tested it and it's up and working - try it)
AU,QLD: 184.108.40.206 (very, very slow - perhaps avoid)
AU,QLD: 220.127.116.11 (fastest of these 3 - definitely try this one too)
OR try these - a bit far away from me but may be closer to you (although Google's servers are said to be fast):
Google's instructions (includes Win7): http://code.google.com/speed/public-dns/docs/using.html
Hope that helps you.