This is really uncanny Reece :hmm: My daughter has recently started experiencing the same problem (using AVG free edition) and I suspect it is either caused by a trojan or a virus.
Tomorrow I am installing ESET Nod 32 anti virus software
....if this is a success I will PM you
In the meantime you could try downloading Firefox and see if the problem still persists.
http://www.firefox2.com/