Connecting both Apple and PCs to the same wireless network

My in-laws have a cable modem hooked up to a dlink wireless-n router. They also have both Macs and PCs. They have always been able to set up the PCs hardwired and the Mac's wireless, and having a password connected wireless setup. However, my brother-in-law just moved back in with them for a closer school, and he got an older PC laptop, as well as my mother-in-law (they were old ones from her work).

Anyway, both are Dells, one is a Dell Latitiude D630 with a Dell 1490 wireless miniPCIe card (so within the case, not sticking out). The other is a Dell Latitude D500, which we picked up a $30.00 wireless PCIe Card for it yesterday. I can get both computers to "see" the network, but neither of them can connect due to the password protection. When I disable the password protection for the wireless network they connect fine, so I know the cards are working fine. But I can't get it to work with a password put in.

For full disclosure, originally the password was 9 digits, lets just say jared5118. I tried to connect, and one of the computers asked for 64 or 128 bit encryption, and when I selected 64 bit, it said the password needed to be 10 digits. So I changed it to jared51182, but still nothing.

On the one we bought the card for, it gave an option of either entering a passcode and generating a key, or entering the key manually, but as I had set up the router with the "jared51182" password, I thought that would work but nothing.

Again, I am more of a mac person for troubleshooting network issues, mostly because I hardwire my PCs, and use mobile Macs. Again, the Macs work fine, they just ask for a password, and get on the network without a problem, but its the PCs that can't connect to a protected wireless network.

Sorry for the wall of text. And thank you in advance for your help.