problem with lenovo laptop useing airport express?

I am using a lenovo laptop with windows 7 professional gold edition given directly from lenovo when I used to work for Microsoft. I just bought the airport express, I also have an ipad and iphone and while always being connected to the Internet and they work great but with my laptop, I only have a 24 hour access and when that 24 hours is up, my wifi signal bar turns yellow and flashes limited. I then have to go through the trouble shooting diagnoses to regain access. I do not understand why this is happening with the airport express when I used the N 300 router for the past 2yrs and I never had this issue, please help...