Computer Hope

I have been logging into and navigating a website regularly for about 10 years.
It is necessary for me to access this website.
Although I am able to login, for about the past 4 weeks I have been unable to navigate within the website. I am using Windows XP / Mozilla Firefox. I have contacted the organisation concerned. They have advised me to clear my browser history, cookies and cache.  I have done this but the problem remains. I would appreciate any help or advice.

Please check the computer Date and Time. If the date is 1999 you may need a new cmos battery.