Pavillion slimline power on.

[Boris_T]

HP Pavillion slimline turns on as soon as power is connected, without having to press on/off button.

[savvy2 · Accepted solution]

no model told full model number or full product ID#

then age of PC is know and lots more.

you found it like this used and cheap or just happened do you out of the blue, (was good say last week)

I guess you mean AC power cord in hand , then inserted into AC wall jack the PC turns on.

that is caused by 2 things, (or power switch bad, nah.)

1: RTC coin cell is bad (CMOS NVRAM COIN cell) below 2.9v is dead. causing BIOS total chaos.

2: is is turned on inside BIOS called Calendar time power schedules seen on some models of PC,  (or simply stated ON POWER restoration do what.  stay off or turn on. ( and is caused by #1 most times, you not going here)

all PCs do this when the battery goes dead (COIN)

the PC is now in CHAOS mode, BIOS goes nuts and totally random failures, all BIOS configurations lost and now random.

This is the first thing to check on all PCs,  for sure any power or bios related oddness of ANY KIND.

first things first is batteries.