Vista - Auto Connect Wireless steps please

I lent my computer to my dad while I'm fixing his. My laptop is on Vista...heaven help me I'm not sure what version etc. (Edit, found my tag its a Vista Home Premium and its up to date with service packs...is it 3? I dont remember) Before he left I set up a guest account and made sure it was all good with the wireless here at my house, all seemed great.

Then he calls me when he gets home and says that he can't get connected to their wireless. I kinda figured I'd get a call, so I logged him on as me, we set up their wireless and then I had him go back to the guest login and same thing, it wouldn't connect. It is giving him a message, something about not being able to connect and to notify the administrator.

SO I had him go back on my account, trying to get him to find how to set up their wireless to automatically connect because it didn't do so. The screens are so different between Vista and XP (what these two computers here have) that I can't walk him through it over the phone so I just have him using my login. I NEED to get this working while I wait for the fix on his computer...

Can someone please look at their computer and give me step by step on how to make a wireless network automatically connect. I'm sure its in there and relatively easy to find, I just can't see what he's looking at and he can't help me find it. (btw this is not a tech issue, I use the computer every day on my wireless here at home and it connects automatically...so it not a case of drivers needing to be updated or anything...just a case of me not being able to see my computer through the phone!!!)

Thanks in advance!!
-trying to remain calm