Only Connects to 5Ghz, Won't Connect To 2.4Ghz

I have no idea what's wrong with my MBP. It can only connect to 5GHz freqencies and won't connect to 2.4GHz freqencies. The only reason I noticed this is because I have two dual band routers. One at my apartment and one at my parents home and my computer will connect to the 5Ghz single but won't connect to the 2.4Ghz signels. I also tried connecting to my girlfriend's wirless b/g router and I get a connection timeout error and when I connect to the free wifi at starbucks I get the same error. Someone please help.