poor connectivity with certain devices

I recently switched over to Comcast.  Ever since the switch, one of my main devices I use (Lenovo Ideapad) constantly drops the connection.  Sometimes it will work with no problem for an hour or two. Other times, I will spend an hour or more trying to make the signal work.   I did not have this problem at all before with my previous service.  I have tried many different suggestions offered through the troubleshooting services.  Nothing seems to make it any better.  

I have had a couple of other devices (like my daughter's Kindle) suffer the same issue. So I know it isn't just my laptop that has a problem.  Has anyone else had this issue?  Is there an easy solution?  
Suggestions?

-Mike