Connection problems

Hi
My broadband is working ok, can browse the internet without any problems but when my software tries to update, ie norton, adobe flashplayer, it keeps failing as it says I am not connected to the internet but but my connection is showing as connected and I can still browse the internet? hope that makes sense.
Both my children are on same network using windows xp and they do not have this problem, its only with mine using windows 7.
Is there something wrong in my settings, any advice would really really be appreciated.
Thanks
Sarah

Hi again
Just checked the event viewer and this is the error that seems to be happening every time, hope this helps

Error 12/02/2010 10:59:00 Dhcp-Client 1001 Address Configuration State Event

I no expert but you can try these and see if they help. You can open up Network and sharing center and click on troubleshoot problems. Then click on network adapter and check it for issues. The other thing to try is reboot your modem, unplug it from the AC power outlet and let is set unplugged for a minute or two then plug it back in.