LUCY FLETCHER

Hello, I have 2 pcs and a laptop working off a wireless router. 2 of the PCs have vista and the laptop has windows 7. I have a problem in that I go into webistes fine, but after I've clicked a few links within the site I get the error message 400 coming up. I have a work PC on a direct broadband line so I have checked the sites on this to see if the problem is with the site and they work fine, so I don't understand why I should have problems on the others. Is it likely to be a router problem? Please help I don't know an awful lot about PCs and would appreciate some help as this is very frustrating. thank you