Either you aren't logged into the forums or you are having problems with the board putting cookies on your machine. Many parts of the site rely on a cookie on your PC with your username and password to log you in automatically. To make sure your PC will accept cookies from the site assuming you are using internet explorer do this:
1. pull the tools menu down to internet options
2. click on the security tab
3. click on the green check mark that says trusted sites
4. click on the button right below that that says sites
5. uncheck the box that says "require server verification (https

for all sites in this zone"
6. type
www.turbodieselregister.com into the box at the top and click on add, you should then see
www.turbodieselregister.com listed in the box in the middle.
7. recheck the require server verification box
8. click on ok twice to return to ie
Then go to the forums and log in. That should set the cookie on your machine and then everything should work fine for you. Let me know.
-Steve