I would not get over worried about BIOS updates, if they have been released by the manufacturer then it has been tested. I have only seen one issue with a BIOS update in 10 years and it did not turn the laptop into a chunk of plastic and metal. Basic stuff when using a laptop is air flow management, ensure it is raised-up to allow air to circulate freely. Another thing is that if the laptop is switched-on/off a lot then then could decrease the longevity of the machine as equipment warms-up, cools down, warms up and this effects certain components over a given period of time.
It might be best to obtain the ultimate boot CD ISO for windows from the internet (google it) and run the tests on the lappy. You might find it is something not related to the motherboard. It could be a memory issue such as a degraded DIMM, faulty hard drive etc but the tests will help you find this out for you.
My initial recommendations would be as follows based upon not finding any hardware issues:
OS restore
1) Back-up the laptop, not sure which OS you have but you can create a complete back-up of the drive(s). Ensure you make a note of critical information, passwords, useful documents, finance related stuff and copy these to a portable hard drive as these are the ones that you'll most likely want first, oh and SWBF2 stuff
2) Ensure you copy all the latest HP updates from the Internet relating to you laptop to a portable hard drive. Make a BIOS update CD or if the laptop is capable and you are confident copy it to a memory stick but ensure the laptop can boot from such a drive (check this out in the BIOS).
3) Restore it to the factory/bare metal restore, you've most likely got a CD or there could be a bootable partition on a hidden drive, check this out prior to flattening the OS.
4) Apply the updates you downloaded, see point (2).
5) Run the laptop without any additional software and see if it crashes/freezes etc
6) If the system is stable begin by loading the software back on, allowing sufficient time to monitor the equipment as software can cause issues such as updated graphic drives causing software to hang, default resolutions to change etc.
Anyway the above should help you out, if not let me know and I'll try and help out where I can.
Regards,
Kren