How can i reconnect to my wireless network?

My computers been working fine all along, its 3 months old. until one day, the connection stops connecting and everytime i try to repair the connection, it wont let me. ive tried rebooting the comp, reconnecting the router...

sometimes when i turn on my computer, or pull out the linksky, and put it back in, it connects for around 2 minutes, then totally disconnects me from my wireless connection

i have 2 other computers in the house that connects perfectly fine, its just this one that doesnt work. and i know it isnt a problem with the hardware. just wondering if somebody has an idea as to how to fix this problem. thanks in advance.