Flashing login screen on HP

Just purchased avg on my hp pavilion laptop. Followed all of the requests from the program to fix this and that. Everything was going good then avg asked me to restart my computer, so I did. Now the problem- the login screen where I should be able to enter my password to get into the computer flashes from the login page to a blue screen then back every second. I tried to type my password then the screen changes again blue to login back and forth. 

Any ideas?

Hello Mike…
That's unfortunate to hear and we regret the inconvenience caused. Please try to boot your PC in safe mode, uninstall AVG TuneUp and restart your PC in normal mode. Let us know if the issue persists.

Click this link for steps to uninstall AVG TuneUp.