MODEM WIFI RESTART WHEN TRY TO CONNECT THE MOBILE

Hi All, 
I'm an Italian guy a new entry in this forum. 
First of all, let me underline the high professional and competence in this forum 
very good questions and answers. 
Then, I've a problem with my modem wifi (fastweb italian operator) that sometime restart   
when try to connect  via wifi my samsung galaxy. 
The modem is new, arrived more or less 4 weeks ago. 
the first two weeks all ok, the last two weeks sometime the modem restart when open the wifi option in my samsung galaxy (froyo 2.2 version I9000xxjpc) probably some app installed that could create this problem. 
Has someone had the same problem?
thanks
Giorgio

thanks for your replay... 
the strange thing is that only with the samsung the modem wifi sometime restart 
I've tried 3 different pc and one htc hd (with the same sim card) and they connect immediately 
without problem every time 
let me know
ciao