Are you saying you can't remove the battery? Probably best to wait for someone with experience of that chassis for guidance as I don't have experience of it. Just seen a few laptops that once you remove the battery there are screws underneath attaching the chassis together so wondered if that...
As per above if it is a PCS build sure someone with knowledge will help. I would definitely check under the battery though as have known a few laptops to have 1 or 2 screws lurking there.
PCS don't normally monitor the forums so if you want direct support from them it would be here (via phone better).
Some troubleshooting you could do yourself can be found here in case it helps.
I'll leave it to better trouble-shooters to help with the issue but I would remove the build info as it has your Windows key on it and that could be stolen. View here on how to show your build info but make sure that Windows Key isn't on it.
The cable to the right doesn't seem to be fully seated from that picture so if you can, re-seating it would be advisable. Also assume the power button at the back of the PC for the PSU is definitely on?
If it runs fine and is only when the monitor is off it is likely a 'false positive' in my experience, effectively it is just a warning to state no connection detected from the GPU to monitor (because it is off).
Is your monitor turned on before you boot the PC? If not turn the monitor on first, boot the PC and see if the beeps are still there. These beeps, if everything performs as normal once it is booted up, may be a false positive just notifying you that the PC can't detect a monitor connection.
Are you sure it was just 2 screws? Searching through the forum posts I have seen another post that indicates 3 screws under the battery for that series of laptop (although it was the smaller version screen).
Might be good idea making sure definitely got all the screws out. Other than that you...
Not sure this will be helpful as I don't have that laptop or experience of it but make sure you have checked that there are no screws under the battery that you need to remove before you can open the casing. I know some laptops have a couple in these places which are easy to miss.
If your PC works fine when booted and boots as normal likely to be a 'false positive'.
Turn your monitor on first then boot the PC, if the beeps do not occur then it's fine and all it is stating is that when it first boots it can't detect any monitor.
I would wait until someone more knowledgeable replies but just in case they don't my next thoughts would be:
Re-seat Wi-Fi card (especially if the PC has been moved since the last time you used it).
I personally would go into 'Device Manager' right click on my wireless card and 'uninstall...
I may have reached my basic troubleshooting limit then! Other than reseating the Wi-fi card and maybe also rebooting the Router(although if all other devices are fine guess it won't make a difference) my 'knowledge' in these areas may have run its course.
I'm sure someone else who is much more...
I can't believe it would be PSU related as if so your whole system would be unstable.
If you felt confident you could reseat the Wi-Fi card just to rule that out. I have seen issues with Windows Updates botching Wi-Fi drivers. Where did you get your driver from? Is it the same driver as per...