Windows 7: Win 7 homegroup creation

I'm running Win 7 Pro. I have all the PCs (all Win 7 Pro) on my network setup with the same workgroup name but for some reason I cannot setup or create a homegroup on my main PC so my other two PC can join. When I get into homegroup from the control panel, the only option I get is to create one. For some reason, I thought there was a second option of to join a homegroup. However, when I click to create the create pop up window never changes. I can let it go and come back in an hour and it's still the same. I use to have a homegroup setup on this system but not sure why it disappeared. Thanks