*URGENT* Need help with network connection!

So my laptop (2008 MacBook) crashed and I had to reinstall OS X (long story), I installed 10.5 and kept my old system (which was 10.6) as a file on my hard drive. Basically its back to zero and so I reinstalled Snow Leopard to get it up to date, only to realise I hadn't set up my internet yet. And as you might of guessed, I can't get it to work. My other MacBook can connect, so can my desktop and my iPod Touch, but I've tried everything and mine can't.
Basically, I tried with every security type (WEP, WAP, WAP2, etc) and every possible password, (with capitals, with space, dashes, etc) nothing works.
I need help, URGENTLY!!
THANKS!!!:Blushing::Blushing::Blushing:

did u tired without security, i mean turning off the Encryption and then try to connect!!

So if you connect laptop with a ethernet lead temporarily it works OK? Is this just a wireless issue?

if u can connect to wirelessly with the security Encryption on it then try to assign a static ip address to you computer inside the router then try to connect and for
Mac address security is not enabled
The client is not an 802.11b or g client trying to connect to an 802.11n network.