Vista - Unable to locate additional network (wireless)

Hi

I have a Toshiba computer using Vista premium and I recently installed the Linksys wireless router. My computer (i.e. PC1) is on "Network" with access to internet by shaw cable. I tried to find my wireless connection but Windows says it is not able to locate any additional networks ...not my wireless or even unsecured internet wireless connection in my area - i live in a tall building. My friend who visits me often has no problem connecting to an unsecured connection - her computer straightly away is able to identify wireless connections without any delays...she is using XP Windows.. I have a newer computer and is having problems...very surprised. I would appreciate if someone can help me to resolve this problem..i have updated the device manager .the Realtech driver ...nothing worked......

thanks