Windows XP ERROR?

yo guys, i was wondering if any of you could give me a helping hand, ive bin using Xp Pro for a while now, and ive never came across anything like this.

the problem as it stands - everysingle webpage link i click on to take me to a download page, that should pre load my download dialog box just says, You are not authorized to view this page, even if im a member of the site. its not my firewall or my internet options as tey are defualt, so if any1 has any idea, without me having to reinstall XP, witch is a bitch :P! cheers.
Aid

try mozilla/firefox?

whats that???

a different browser