Ipad can't connect to wifi

Question

Why won't my ipad2 connect with wifi.  MacBook Pro and PC work, original iPad works and iphone3G recognizes it, although not very strong.
I tried Powering Off and Reset Network Settings but still not connecting.  The iPad2 recognizes the wifi with fill strength, when I go into settings
and choose it there are no codes or numbers in IP,Router, DNS, etc., where as on the original iPad those fields are all full, I can not manually enter any.
It worked in the past OK but the signal was really poor in some areas of the house, we tried another router which did not work for other reasons and hooked this one back up, and now I have nothing.  What do I try next.

Answer 1

I don't know how it answer or get some details, maybe some guidance will help.
This is what I can tell you :
We have DLink DIR625, not sure how to find out what version or firmware level
We do not have a password on the system (we are in the country with no neighbours to interfere)
Can I find the answers for these questions asked somewhere on my computer?
My iPad2 does work on other networks
In System Preferences under Networks on my MacBook Pro, I have the following info:
Configure IPv4 : Using DHCP
IP Address : 192.168.0.127
Subnet Mask: 255.255.255.0
Router : 192.168.0.1
DNS Server: 192.168.0.1
Search Domain: sympatico.ca
On iPad - original older version
IP Address : 192.168.0.167
all the rest of the details are the same
On iPhone 3GS
IP Address : 192.168.0.117
all the rest of the details are the same
These 3 items all are currently working fine
I can not access my husbands PC, so do not know what those codes are on his.
On my iPad2 all these feilds are blank and I can only manually enter in the
DNS Server and Search Domain sections
Any other guidance would be greatly appreciated