IS there a specific code BESIDES AO that it hangs on during the beeping sequence?
The beep codes would seem to indicate that is is a hardware issue, not software, because no windows related software or settings are even initiated at any point during the time in which the motherboard runs it's POST test sequence, therefore anything related to Windows settings, drivers or configuration could cause the motherboard to beep.
Plus, if it was related, it would do it during restart as well.
I think the first thing to try is going into the bios and checking to see if the date and time are correct. If they are not, replace the motherboard CMOS battery. If they are, check to see if the boot order is correct. If they are, I would try doing a hard reset of the BIOS using the following procedure.
Power off the unit, switch the PSU off and unplug the PSU cord from either the wall or the power supply.
Remove the motherboard CMOS battery for five minutes. During that five minutes, press the power button on the case for 30 seconds. After the five minutes is up, reinstall the CMOS battery making sure to insert it with the correct side up just as it came out.
Now, plug the power supply cable back in, switch the PSU back on and power up the system. It should display the POST screen and the options to enter CMOS/BIOS setup. Enter the bios setup program and reconfigure the boot settings for either the Windows boot manager or for legacy systems, the drive your OS is installed on if necessary.
Save settings and exit. If the system will POST and boot then you can move forward from there including going back into the bios and configuring any other custom settings you may need to configure such as Memory XMP profile settings, custom fan profile settings or other specific settings you may have previously had configured that were wiped out by resetting the CMOS.
If the system will not POST after resetting the CMOS, then there is a hardware or BIOS configuration problem of some kind. Go back into the BIOS and make sure that the time and date are still correct and that the boot order is right. Also, since you are running Windows 7, make sure that in the secure boot settings it is not set to UEFI/Windows 8/10 but rather to "other". Also, find the compatibility support mode setting and make sure that is set to CSM enabled, since Windows 7 does not fully support UEFI configurations.
You will also probably need to reset the memory XMP profile settings if your memory is supposed to be faster than 1333mhz.
Truthfully, you may have a dying motherboard happening, but try these steps first and see what shakes out.
It would also be a good idea to double check that the memory and graphics card are both fully seated by removing and reinstalling them.