Need help with WRT54g

[Vikings360]

I live in a 3 flat (apartment with 3 floors). I live on the third floor, and my parents live on the first. The building is made out of brick. My dad owns the building, and I live on the third floor. My router is on the first floor with my parents. I have 2 wireless belkin 54g desktop cards. I was able to configure my parents' pc with the wirless internet connection. The problem is that my own computer on the third floor doesnt even see the SSID the router broadcasts. I cannot establish a connection because I dont see the SSID. The settings on both pc's are the same. They also have same OS. I installed the sveasoft firmware too. I dont understand why the computer on the third floor is unable to catch the SSID of the router for a connection. Is the range not getting through? What are my options?

 

[Fiveohhh]

try bringing one of the computers on the top floor to a lower floor and eliminate if its the range.