Boot and BIOS issues

I have a windows laptop that is getting a little old so I installed a dual boot system using GRUB and UBUNTU so that I could use a quicker running system when required. This worked fine for months however Ubuntu opened yesterday and said it needed to update, I installed the update and it prompted a restart… upon restarting all I get is a black screen indefinitely! GRUB won’t load up, I cant choose an operating system to open or run, the BIOS and UEFI doesn’t appear to be there any more and won’t allow me to access it to try and boot from a usb or anything, a simple update appears to have rendered my laptop completely useless and I have work documents on there that need to be recovered. What on earth has an update done to remove both grub and access to the computer bios??

This answer may be converted to a comment (which is what it probably should be) - but I don’t have commenting rights at the moment! Assuming no major hardware fault, you should be able to retrieve your data: you’ll probably still have the installation media (if not, create another usb stick); boot in to that using ‘try Ubuntu’, and you should be able to mount the laptop hard drive to access your files / copy them to another usb storage device. You can then try the various grub repair options to try to get it all working again, but I’d suggest trying to backup the data before attempting any boot repair. Good luck!