Wireless Networking Freezing !!

Hello please oh please could some one help me with my laptop , i am running

Microsoft Windows XP Media Center Edition 2005

and up untill a while ago it was working fine and i change a lot of things in a day so i dont really remember what i have changed.

Here is my problem i can connect to A wireless network , i right click on the tele at the bottom and choose "view available wireless nwetworks". It all works fine . I then click on "change the order of the preffered wireless networks" . my laptop explorer freezes i can access task manager but if i try ending explorer.exe then running explorer.exe again it stays frozen.

Is this a hardware of software problem ?

Is it easyily fixed ?

Thanks in advance ....