error code confusion

Question

On my optiplex 790, i get the code 12 4 then 3 then 12, if it starts up normally it will flash some other codes then go to nothing and start up normallly. if it stays at 1 2 blue power light, it will stay then beep and stay at 12 forever with no display or anything. Sometimes the pc black or white screens and upon rebooting, it goes to the 12 loop as mentioned before. I am currently testing other things such as mobo or psu failures and want to exclude an issue. is there anything i can do to fix this or is there any causes for this. i have heard the lights for older systems can be unreliable. it would be greatly appreciated if someone could help out.

redxps630 · Answer

replace cmos battery with a new CR2032 then clear cmos settings via mobo jumper.  will save you a lot of woes on dx code.

pcuser451 · Answer

ok so i replaced the cr2032. i tried the cmos clear but when i put the thing on the two prongs it didnt start or give any signs of life at all,  and when i put it back on the original one it started fine. i cant find anything online about exactly how to do it and if it should turn on or not. what i did exactly was take the blue thing from one of the prongs to the other one, plugged it in, no sign of life. put the blue thing back on the original one and it had turned on fine and went back into the 12 loop i said before. do you know how to actually do it and what to do because i cant find any actual guides

pcuser451 · Answer

ok nevermind my previous post, i did it right but it made no effect on the issue so it wasnt related to that. i looked at the entire pc to see if a cable wasnt plugged in right but no. i cant find anything wrong with it. :(

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error code confusion