Just today, my Toshiba Satellite P750 (running Windows 7) has been disconnecting from my wireless network when I wake it up from sleep mode. When I close my laptop lid, it automatically goes into sleep mode, and when I open it up, I put in my user password and use it as usual. However for some reason today, it's not working.
When I wake it up, it recognises that my wireless network is available, however can't connect to it. When I troubleshoot the issue, it states that there is a problem with my router and that I should turn it off, wait at least 10 seconds and then turn it back on. I've tried this, and it works fine, however my laptop has never done this (in the few weeks that i've had it) and I shouldn't have to constantly reset my router in order to use the Internet. Furthermore, I have another laptop in the household which works fine.
Would really need this issue resolved quickly as I have exams this week.
Possibly there is a problem assigning the ip address automatically after the notebook has been set to sleep mode. It could be also another reason for that but it’s always difficult to say what could affect the wireless networking…
I think that you should try to update the Wlan driver.