Trouble Logging In

hi

i was wondering if someone can help me out with this hassle i am having

the last couple of days ive had to keep logging in

even with the remember me ticked

and when it decides to keep logged in it says welcome Guest ?

then i go to the forums and it says welcome vindictive666 ?

i am using firefox version 3.0.3

no problems with other forums


sorry if this has been posted before

even searching for a answer is proving difficult ?

regards john