If you can get back into Last Known Good Configuration, uninstall the latest updates and see if it will boot normally. If you can't get back into LKGC, try Safe Mode and uninstall those updates.
A repair install seems rather drastic as it will wipe out every update on the machine since the pressing of that disk. You need to uninstall those updates, then you can install them one at a time to narrow down which is the problem child.
Nothing wrong with checking your hardware. Things do sometimes happen simultaneously. Verify the hardware and move on.
My computer booted to a black screen with a blinking cursor last week. I had disconnected my hard drives and temporarily installed some others to run a scan on them. After that, a blinking cursor boot for me. I removed a CF card I had mistakenly left in the reader and it booted normally.
I can't explain what happened or why. Just a weird thing.