Dave and others here are definitely on to something. My experience is not too over-focus on one problem and stay stuck there. Move on. I give you an example.

I started this course on March 1st and play about 1 hour a day (so you have some idea of my experience.) Very early into the course I wanted to 'master' strumming along with rock songs I liked. So after I learned most of the open chords, I decided I wanted to play Man on the Moon by REM. Why? because I love the song, it's all accoustic, and it only has the chords C, D, Am, G and Em. But guess what, the verses have this switch from C to D and back and it caused me problems. C is a hard chord, you feel like you are forced to place down one finger at a time. I addition, the chorus has rapid-fire chord switches between Am, G, C and D again. It was absolutely hopeless.

So I decided to give this one a rest and move on, and focus on simpler songs with easier chord progressions and fewer chords.

This week, though, I tried to give Man on the Moon and new try. And almost miraculously all fell into place. In less than an hour I could play along with the song, at normal speed, and hit all the chords right. Now it feels like a dead-easy song. And what's more, it's the first song where I can actually play along AND sing along at the same time - which for a beginner is really hard.

I think the reason I all of a sudden have this song down is I practiced and practiced on other stuff and became better and better at it, instead of playing Man on the Moon for 8 weeks. As an added bonus, I now not only play Man on the Moon but 5 other songs. Also after playing C a million times I noticed that when my brain says 'C', my fingers almost automatically form the shape in mid-air before placing them down. Which is what you want, but it only comes after a lot of practice. Again, the key is not to get overly hung up on this one obstacle. Better to move and and revisit later. By move on, I mean try other songs with either fewer chords and/or different chord progressions for the same chords. Build from there. I guarantee you that this will solve itself.