I doubt that is caused by ram.
Run memtest86 or memtest86+
They boot from a usb stick and do not use windows.
You can download them here:
MemTest86 is the original self booting memory testing software for x86 and ARM computers. Supporting both BIOS and UEFI, with options to boot from USB.
Memtest86+ is an advanced, free, open-source, stand-alone memory tester for 32- and 64-bit computers (UEFI & BIOS supported)
If you can run a full pass with NO errors, your ram should be ok.
Running several more passes will sometimes uncover an issue, but it takes more time.
Probably not worth it unless you really suspect a ram issue.
If you eventually get a good looking screen, the monitor is probably ok.
If you never get a good display, look to a graphics card issue or possibly a cable connection issue.