Hi,
As above, check your wifi router and ensure you have the correct password. Perhaps re-set it and don't forget to update on your other PC as well or then it won't connect!
If it still doesn't work, you may have to delve further into checking the wi-fi setup on the router and then ensuring your iPad is configured correctly, perhaps the router has a PSK2 encrypted password and you are on your iPad and trying to connect via WEP?
Not much more can be done via here, so perhaps give apple support a call?
Cheers, DtM! West London & Slough UK!