Looks like my last post disappeared. Don't have disks though updates arrive fine so must be gen Windows. Old IBM laptop had a fleeting BIOS page on startup but not this Compaq so I'd need to know how to get in. I watched the 'Replace backlight' (thanks Simon G) and maybe the laptop watched it too as it does seem to be reasonable of late. It was really grey before though still perfectly readable.
Thanks again to all