Hi, I've had the same problem as first mentioned.
Had my 5550 for several months, no problems, then the said problem would arise just when I wanted to use the Wi-Fi for connection.
I have had to hard reset at least 10 (yes 10) times over the last few weeks each time loading my programmes one by one.
In the end I got absolutely fed up (that was to put it very mildly) with the whole experience.
I very nearly reverted to my old and trusty 3970, then I performed one more hard reset, but this time I did not install a programme (a virus checker) which I'd only been using for a short while and hey presto (at the moment) all seems to be in order and complient!!!!!
I've always installed the latest drivers, firmware, and ROM Updates so my 5550 has always been 'topped up' so to speak in order not to miss out on anything important or neccessary to help the performance.