Try it without USB devices but let's get down to the ugly truth. Most laptops come with restore media so repairs are limited to Windows Error Recovery, System Recovery (see google) or restoring to the factory load which tests most owners backup prowess.
In closing, be sure to not omit details like the exact model number. For example dv6 is not a model number but a line of models that start with dv6.
When I turn on the laptop, it seems okay, until it shows the Windows Error Recovery. It asks which option I want to choose
-Launch Startup Repair- or -Start Windows Normally-
And if I pick either one, it looks like it's going to go to the login screen, but it's stops loading with just the background of the login screen.
I've tried removing the battery and running it w/ the power cord.
I also tried running it in safe mode.
It uses Windows 7 if that helps at all.