how can I create wifi hotspot on windows 7 that can be shared with my macbook?

My USB modem has issues so my Mac doesn't recognize it. I created an ad hoc wifi hotspot on my Windows 7 laptop with WPA2 encryption and shared the internet. My Macbook Pro sees the wireless network but when I enter the password I get a connection failed warning. I tried connecting also with my iPhone and before I entered the password I got a messag/e that "MyWirelessNetwork" is not connected to the internet. How can I solve this issue