Gigabyte mobo internal speaker long beep when im using pc

Hi All.

My workhorse dinosaur that ill be upgrading soon is doing something weird.

I'll be checking my emails in a web browser and the internal mobo speaker will do a long beep (once) and then the fans do that initial boot up speed whirr as though all the system is waking up.

I don't get any crashes or anything, temps seem normal is this something I should be worried about?

Thanks for any help