Login Session keeps expiring!

[sunon]

I have a problem with my session always expiring, every time i login to joomla code it will either allow me in but after clicking a link to another page, i will be asked to login again else, after clicking login, it wont even log me in, it will return to the login page again.

it is not that there is a problem with the password/username since it gives no error - but it means when ever i wasn't to use a tracker, i will need to keep pressing login until it finally allows me in, agian having to press login when i now want to submit the tracker.

I am running on Vista Business, Firefox 2.0.0.9 - i have even tried Internet explorer and it as well wont allow me in.

Something i have thought of - the network im on uses a cache server, is it possible that this could be causing me to log out all the time.

Thanks

[sunon]

Problem fixed