Ray - You told us your problems started when you upgraded your computer and you say you don't have a problem on other computers. As I said in the beginning if you chanced you links to wwf from ..com.au to .com and there was still a problem then it would be at your end.
As I said before it appears that a program or setting somewhere on your computer or browser is deleting your cookies You need to find what is deleting them - most likely browser - and set en exempt for woodwork forums cookies.
If you haven't already done it.... The last thing for you to try is to delete your browsers cache. and any forum bookmarks you may have stored then start from scratch by loading the forums via this link
Woodwork Forums - Powered by vBulletin
The links below are to wikiHowand will guide you through deleting cache from the following browsers:
It.s pretty obvious the problem is not be with woodwork forums or we would be getting thousands of complaints.
It worked for you before your computer upgrade, it works for you on other computers. It doesn't work on your upgraded computer. Simple deductions says the problem is somewhere in your computer.
Cheers - Neil :U