I built my computer 8 months ago. 6 months later, the mouse pointer started lagging so bad it was unusable. I tried some fixes but nothing really helped. The next day, my computer didn't work. POST says it's the graphics card. Okay, I got a new one. It arrived today and I put it in. Nothing has changed. The fans on the old one worked, so it had power. Did I misread my beeps or do something else wrong. I know enough to build a pc, but not enough to troubleshoot it.
This is my motherboard. It doesn't have onboard graphics.
As requested: 1 long beep, 3 short. No unusual flashing.
It powers on fine and everything appears to be working inside, but it does the beeps and doesn't show anything on the monitor.
This is the power supply.
A few things, your CPU is the component which would host the on-board graphics not the motherboard. Intel CPUs that do not have an -F in their model number have on-board graphics (11400 or 11600K for example) so knowing what model you have may clarify this.
I assume that the system is no longer able to POST even with the new graphics card installed? This likely indicates that it is an issue with the motherboard itself potentially having a damaged connection to the GPU (just a guess). It would also be helpful if you have a recording of the beeps to help you confirm the pattern.