I upgraded my dell studio15 laptop with Windows 7 from Vista about a month ago..
My internet connection (ADSL Broadband Connection) gets disconnected intermittently so had to reconnect to internet when I had Vista installed.. but ever since I upgraded to Windows 7, internet connection is getting disconnected very frequently and as soon as I get disconnected from internet connection, my laptop stops responding for a long time(around 5-7 minutes).. and everytime I have to remove the network cable and wait for OS to come out of NON-RESPONDING state.. what could be the problem? how do I resolve it?
It could be some Malware/Spyware, but of course the first thing popped up in my mind was registry. Try to clean your registry with http://www.piriform.com/ccleaner
and remove malware/spyware with http://www.malwarebytes.org/mbam.php. I had the same problem with my HP laptop Vista, the network still gets disconnected but overcomes the Non Responding State.