update caused re boot failure

Have pc xp3 Gigabyte mobo using avast free basic setup 10.3.2223
Yesterday had program update and required reboot . Pc rebooted but blank screen.Several manual reboots later accessed windows startup.
Pc slow and sluggish so after several hours use decided to uninstall Avast free and reinstall. Boot up failed. Could not use optical drive or access boot options or bios settings. Only got splash screen for mobo and then blank screen.
Eventually powered off pc drained residual charge by keeping power off and switching power button on.
Rebooted fine but with several security window updates previously installed.

Q. Did update/uninstall effect my CMOS/BIOS and why?
Do I use Avast again?

skip

avast does not even comes close to a bios.
What you describe sounds like a little problem with the graphics card.
The beep(s) you hear when booting are telling the problem.

@ skip888

There are others with xp issues.
https://forum.avast.com/index.php?topic=173676.0

https://forum.avast.com/index.php?topic=173591.msg1233252#msg1233252