CRTs don’t last forever, and neither do the electronics that drive them. When you have a screen starting to go wonky, then ...

You mostly do not need to worry about pitfalls of concurrent processing (races, deadlocks, livelocks, resource sharing, etc.). The fact of cooperative processing takes care of such issues by design.

The DisplayPort to VGA Adapter not working issue is usually caused by having the wrong drivers installed. To start fixing this issue, it is recommended that you use a reliable driver-updater software.