Please Help. Internet dropping out

Bigpond is wireless cable connection am I correct? If so and you are having DNS issues it lies somewhere with your server dropping connection to your radio. You may need your radio replaced, you may need your ISP to give you another IP or switch frequency channels for you to not receive interference from other devices using same frequencies. You may be on 2.4 GHz radio frequency and that can get interference from many household appliances such as cordless phones, cell phones, games and so on. If you can get to your radio look at it and see if your signal is good. Have you checked your ethernet card? Try switching channels on your router, you may be conflicting(interference) from a neighbor on same frequency. If it is set to 1..try 3..or try 6...or 11. One of these may be your issue. Let us know.

I am just curious... Have you tried connecting this machine directly to the modem and bypass the router. If you connect direct to the modem and the machine works then your problem lies with the router, if not then the problem is with your machine.