Sites such as those need to set a cookie on your PC. How are your cookie settings configured? You need to allow them if they're blocked.
i had trouble registering as a member or logging into certain websites.
an example would be http://www.nature.com/ or www.studentcents.co.uk
they either make me fill up my details all over again or say my password do not match, although i have tried logging in using a friend's pc and it works.
is it a browser setting prob? or pc settings? or are there codes on my pc?
browser setting i have changed to default, and i have lavasoft and ad-aware (just uninstalled) and norton antivirus.