clear cookies and cache
perform available key updated for ie
if router/modem is wifi enabled, disable wifi (to isolate problem)
perform multiple ping tests (start>run>cmd> "ping www.ato.gov.au"
check for packet drops if any.
try a different computer for testing purposes
perform a speed test at www.bigpond.com >help> downloads> download "online storage application" look out for speed below 35KBps.