I have a Compaq sr1108an and need to update the bios as it is a early version bios but don't know how to. I have a USB stick but I've never done it before and can't start pc as I installed a wd sata hdd but it won't recognize it. Any ideas what to do
Why do you need to update the BIOS?
I do not think a BIOS update will help you detect a HDD on a SATA port.
That motherboard supports SATA I ( 1.5Gb/s) and I don't think is forward compatible with SATA II (3Gb/s) or SATA III (6Gb/s ) hard drives.
You might need to get a SATA I ( 1.5Gb/s) HDD or a SATA HDD that could be made compatible by software or hardware.
Some SATA II & SATA III HDD might allow to function like a SATA I ( 1.5Gb/s) with software provided by HDD manufacturer or by placing a jumper on the HDD.
The last time I did something like that was with a Samsung HDD using Samsung ES Tool app and that was more than 10 years ago.