My z790-e motherboard is displaying a bunch of q-codes while system is on, they are all the numbers from 29 to 45. Applications and games on my desktop also randomly close, games just turn black and gone the next second. Other than that there is no problem
Motherboard: ROG STRIX Z790-E
Processor: i7 13700KF
Memory: G.SKILL Trident Z5 32GB 6400MHz
GPU: RTX 4090
CPU Cooler: Noctua NH-D15
Power Supply: Corsair RM1000x
Check the BIOS manual - I think the Q Code LED is displaying your CPU temperature. I don't have your board, but some offer that feature. If I'm correct, there will be a BIOS setting to turn that feature on/off. The problem with apps crashing is probably not related. Maybe a drivers issue.