Hey there! I own a 17R 5720 Dell Inspiron on windows 8.1 and I've been having the above problem for quite a while now. My laptop will start up just fine, however, regardless of whether I click on it or not, no applications will run until my sound device is able to make noise. I found this out thanks to Skype. Nothing on my computer would run until it was able to output the Skype startup tone. So, as my curiosity expanded, I restarted and opened the sound mixer on my taskbar and clicked the meter to hear the ring demonstrating the volume level. Nothing. All startup applications and anything I clicked on (chrome in this case) didn't start up until minutes later when the ring from the sound bar and the Skype charm all blasted from my speaker at once.
After that, everything caught up.
I've been dealing with this for a while now, but it's progressively gotten worse. I just waited five minutes from my click on the sound bar before I heard the tone, maybe even more.
And if this helps: Sometimes when I boot up my laptop, the volume icon on the taskbar wont be there, even though I look in the control panel and it says that it is showing.
Any help would be super awesome!