HP doesn't support Windows 10 on the Presario CQ56 series (it doesn't have any Windows 10 drivers for it).
Only Windows 7 is supported.
That may have some bearing on your current problem, though that's just a guess to be honest, but it can't be a coincidence that the problem began when you upgraded.
With laptops especially, you should always check the laptop manufacturer's support pages before going ahead with an OS upgrade or downgrade.
All I can suggest is you revert to Windows 7 via the Factory Restore discs if you made a set, or if the Factory Restore on the HDD is still intact & usable, use that method by invoking it at boot time.
It's either that or continue using Windows 10 on it from mains power only, obviously...