Cant click on a picture link, please help.

Hi,
Keep getting a message come up asking to allow something to connect to the internet, I block it happens everytime I use the pc. Anyway since this has been happening I havent been able to click on a picture link. Just wondered if anyone could possible help me please? Hoping it will be something simple??!! Oh I have windows Xp if thats of any use?
Thanks in advance!
Babs.