because in theory an operating system update should have no effect whatever on the way a wireless router works. The router's firmware holds the authentication information necessary to establish the connection with your ISP (or your modem does, if the router doesn't have its own), and the router simply broadcasts a radio signal. The first time an operating system has any say in the matter is when the wireless network card picks up and relays the signal into the O/S.
Whe you say you get 'drop-outs' do you mean that the router stops transmitting (which happens with my Netgear router at least once a day, SP2 or no SP2), or do you mean that your network card drops the signal, or that the signal is disrupted within the building? I have set up dozens of these networks and although they mostly work pretty well I have one client who drives me mad with his tales of lack of access and dropped signals - he refuses to accept that the problem is his three-storey multi-doored Victorian house, and the fact that he wanders around it, laptop in hand.
My own home wireless network trundles along pretty nicely most of the time, but this Netgear router seems to be the worst I've had (of three) for suddenly stopping transmission. It stays connected to my broadband ISP, but none of the computers can go online. Maybe I should ask some suppliers if they'll send me a selection of routers so I can run an in-depth test. On balance I love wireless networks, they are the perfect example of what technology should be doing for us.........removing obstacles and freeing us to work wherever and whenever we like.