Older HP Pavilion dv series laptops can have this kind of boot problems sometimes when either the battery or motherboard is coming closer its life cycle. The laptop simply can't start the POST (Power On Self Test) and can therefore not boot. That your issue occurred first time just after you installed a new application and got a blue screen can be a pure coincidence.
You could try this to completely reset your laptop:
Turn the laptop off
Disconnect the power cord, remove the battery
Press and hold down the power switch of the laptop at least 30 seconds
Wait 15 to 20 minutes, plug the power cord back. Do not insert the battery yet
Turn the laptop on
If it boots normally now, turn it off again when Windows has booted normally, replace the battery before turning it on again
Thanks for the link, Bob, I am going to bookmark it.