Xperia Arc S - WiFi wont work. Brand new!

Hey guys,

I bought my self the Xperia Arc S yesterday and when I got home I connected to my router with a 128bit WEP encryption. It worked fine for about 2-3 hours. Then all of a sudden it just stopped working.
I was just checking my email when the WiFi dissapeared.
My laptop, other phones here work fine with the WiFi, its just mine.
Ive read the other threads and tried the following:

Factory Reset
Repair Function from the PC Companion
64bit WEP encryption (and others)
WiFi Fix Apps
WiFi Sleep policy set to Never.

Nothing has worked up to now.
It still won´t connect to my WiFi, it does find it but when I enter the key and press connect it says "Scanning" --> "Disconnected."
It does this with in 3 seconds.

I have not tried leaving my WiFi open but I can not leave my WiFi open since I live in a densley populated area in which people will take advantage of it.

Anyone have an idea how I can make it work?

Thanks!

Yeah, well I actually spoke to customer support and they clearly had no idea what to do about it and eventually told me to have it replaced.
Im not really sure if Im going to do that though since so many people have this problem I really dont think it will change with a different handset.

Either way, I figured, if you unplug your router (just the power cable) and plug it back in the WiFi reconnects and stays connected as long as you don´t turn your wifi off on your phone.
I would say it stay connected for a good 3-4hrs so considering a router takes about 30 seconds to restart its really not that much of a deal.