How to Enable POP-UP's

Hello my name is "congapas",
My question is , That I'm running a "Laptop" "Toshiba Satellite" with windows 2000 "pro" sp4.
I am having problems with "POP-UP's" I can not enable them while I'm on the internet.(As simple as opening the link to complete my regerstation "SYSCHAT")
How could I "enable" I had tryed just about everything. Any & all suggestion would be helpful.
Also if it make a differance I had bought this "Laptop" at a yard sail...Oh one more thing anyone knows why it might not take my " XP Home edtion "??

Thank for any & all replys "congapas"