Why doesn't my new wireless doesn't open internet pages?

[Anna]

I just installed my wireless connection, even though I have a PC. When I plug it in the normal way, it works really well [e.g. right now]. When I try to open some pages through the wireless network, they don't work. It does open some pages [Twitter and Youtube so far] but for the rest I have 404 error.

Any ideas what I should do? Thank you!

[Stefan]

This might seem silly, but it's happened to me a few times. Make sure you are connected to YOUR wireless network. There are many times my computer automatically connected to another wifi and I had to manually connect to MY wireless network.