that post sequence is ram related. try reseating the ram.
Remove all the memory modules, then install only one module in slot 1, then see if the system boots and if the computer starts normally, reinstall an additional module.
Does not boot, move the module to slot 2 and again see if the system boots, no boot, try the module in slot 3, no boot, try installing in slot 4.
Still does not boot, then remove the first module and using the second one, repeat the sequence described above.
Still no boot, try installing any remaining modules, one at a time, using the above procedure.
Continue until you have identified a faulty module [or slot] or reinstalled all modules without error.
Still does not boot, buy new compatible memory module/s and try them.