Repeated BSODs with different stop codes and new display lines

My PC has been crashing repeatedly for the past two days with several different blue-screen errors, including SYSTEM_SERVICE_EXCEPTION, KERNEL_SECURITY_CHECK_FAILURE, KMODE_EXCEPTION_NOT_HANDLED, and PAGE_FAULT_IN_NONPAGED_AREA. Windows Memory Diagnostic found no RAM problems, and System File Checker repaired some corrupted files. Temperatures look normal. I also noticed many Event Viewer errors saying the NVIDIA LocalSystem Container service terminated unexpectedly, so I performed a clean NVIDIA driver reinstall. The computer lasted one or two hours afterward, but the crashes returned. My monitor has also developed faint horizontal lines, which makes me worry about a hardware issue. I have several minidump files available for analysis. What should I test next?