bios/RTC missing off motherboard?

[Phasecoder]

Ok guys I have a Hp presario CQ57 when starts fan starts but gets faster and faster eventually shutting down after sometime ill explain bit more

first boot after pressing power to drain, or after leaving stood for a while, power on and would get the following boot message:

The CMOS checksum is invalid.
The CMOS will be reset to the default configuration and will be rebooted.
Please check your BIOS Setup options to see if they changed.
CMOS Reset (502)
ENTER - Reboot the system

enter is unresponsive and the laptop will power off as if there is no battery connected and the plug is unplugged. On start up again, I done see this, i see the "press esc for start menu,i can get into this for about 20 secs before shuts down again, but can see all sorts options.

Anyaways I took the laptop apart after being told dust etc but was rather clean.
But on looking at the same motherboard on the net and mine noticed my RTC/BIOS is unplugged and missing.

My question is, is this is whats causing the laptop to shut down and the fan run fast before it cuts out? I have ordered the part this one:

http/www.ebay.co.uk/itm/360774149030

Anyone please offer me any further assistance?

Thanks in advance

 

[C12Friedman]

Two things here;
1) yes replacing the RTC battery should help the laptop calm down (that was going to be my suggestion but you've already ordered one)
2) When you looked in the laptop to see if it was clean, did you remove the fan so you could observe the vents? I ask because often I come across laptops that appear rather clean only to find the vents completely clogged with dust

 

[Phasecoder]

so replacing the battery will stop the laptop shutting down, and the fan getting fast??
I meen i dont even see the start screen the brand splash screen.
the fan vents are very clean, is there anything else you can think of that causes shut down?

thanks

 

[Phasecoder]

Two things here;
1) yes replacing the RTC battery should help the laptop calm down (that was going to be my suggestion but you've already ordered one)
2) When you looked in the laptop to see if it was clean, did you remove the fan so you could observe the vents? I ask because often I come across laptops that appear rather clean only to find the vents completely clogged with dust

so replacing the battery will stop the laptop shutting down, and the fan getting fast??
I meen i dont even see the start screen the brand splash screen.
the fan vents are very clean, is there anything else you can think of that causes shut down?

thanks

 

[C12Friedman]

The CMOS battery being missing (or failing even) can cause all kinds of strange behavior in laptops - it may calm the fans down. If the heatsink was removed in order to check the vents and fan, any thermal compound needs to be cleaned off and replaced.