Audacit won't replay my labeled words. [SOLVED]

I am so frustrated I could scream. I have re-installed Audacity three times because I can no longer play back my audio waves so I can edit labels that are not syncing correctly with my smil files. I highlight the words and play but nothing plays back. It worked in the morning but nothing in the afternoon. The audio is working on my computer. I tested it on Youtube and some other files. None of my audacity files are working except the actual m4a files. They all work except the some of the words don’t sync in the book. I am using a logitec headphones and usb to record and playback. I looked at the settings and they are correct. I don’t have a green play button on my audacity screen. It looks like two light purple arrows pointing right. The red stop- button in still there. I have to get this book working. Audacity won’t work even work with a new file. I am using windows 8 and audacity 2.1.

Please help,

Janis

Reinstalling Audacity will make no difference.
If you have an incorrect setting, you need to either reset it correctly, or reset the Audacity Preferences completely. A normal install does not reset the Audacity preferences.
If you wish to reset Audacity Preferences to their default setting, reinstall Audacity using the recommended Windows Installer (from here: Audacity ® | Free, open source, cross-platform audio software for multi-track recording and editing.) and select the option to Reset Preferences during the installation.

Audacity does not support smil format.

What changed between the morning and the afternoon?

Does your Audacity screen look like this: Audacity Manual

There is no “Audacity 2.1”. Do you mean “Audacity 2.1.0” or “Audacity 2.1.1” or something else?
Look in “Help > About Audacity” for the exact version number.

I figured it out. I changed the output to MME and it worked. The little floating panel was covering up the start and stop buttons. So not knowing the program that well, I had a lack of perception about what was happening. I thought my computer was have a nervous breakdown, but it was just me.

Thanks so much for the help. Your advice motivated me to figure things out rationally.

Janis