you could run some sort of memory test to verify the RAM is good as sometimes flakey RAM can cause errors.
Well that is true too, Windows 11 will probably use more ram than Win 7 does, so it may be getting to a bad spot too. but Unlikely to be causing a BSOD on boot, so probably not worth spending time on until you can find a stronger graphics card for it
The RAM can be a thing. On an older system I had, I ran dual-channel RAM on a system that would install and run Win7 just fine without stability issues, but then when I would install Win8 on it it would crash frequently. In the end, it was the RAM; when switching to another set the issue was gone. Yet, not an issue on Win7
Remove all memory sticks and try 1 stick at a time and see what the results are and note if 1 stick acts weird to the others, you have 4GB stick each which is enough to install any windows as I have done it many of times, but you need to use the 1 single stick in a dedicated slot so here is the manual - https://www.asus.com/me-en/supportonly/p7p55d-e lx/helpdesk_manual/ Look for the memory management in the manual, and go from there. Also the older the system is the more issues could plague it, I had a mainboard go bezek because of the capacitors, the capacitors lost the electrolyte fluid from age and caused a high voltage or a low voltage in the mainboard which is a bad mainboard at that point, the mainboard could have issues that are not see until testing ( I have been there many times LOL ) Also the graphics card can have the same issue with the capacitors degrading due to age. I had a power supply go bad and it was a good power supply, they put FUQQU capacitors in the power supply well they went out quick, I bought a cap kit and replaced them and that power supply from 2004 is still going today I just use it for testing. Try a spin hard drive in the system to rule out weirdness with the hard drive.
