I downloaded Windows Defender on 9/10 because it has free real time protection, but I think something is wrong?

I was having a hard time finding a AntiSpyware Program that is compatible with the Comcast McAfee Security Suite. I had originally had installed Spybot, Spyware Blaster & SUPER AntiSpyware, but they weren't compatible with McAfee so I spoke to a Tech Support Rep. & he told me to uninstall all of them & go find an AntiSpyware Program compatible with McAfee. I went to Windows Marketplace & downloaded Windows Defender. It seemed to be working fine at first, but I was still looking for another AntiSpyware Program & someone recommended Malwarebytes AntiMalware so I installed it yesterday. I have the settings to set scan daily, but Windows Defender keeps saying: You haven't scanned your computer in 3 days. We recommend the you schedule Windows Defender to scan your computer each day. I scanned my computer last night before going to bed, but when I turned my computer on this morning it was still saying I hadn't scanned my computer in 3 days, so I scanned it, then about an hour later it said it again. Is something wrong with Windows Defender? Is this happening because I installed Malwarebytes? How can I get it to stop showing me that alert? I went to tools, but I can't figure it out...