BIOS VERSION/MOTHERBOARD

I need to find out what model motherboard I have. I know it is an Asus. I have an HP XL916, Celeron 850 MHz. ALso I don’t know how to make sure I have the most recent bios version installed. I am having problems with slow downs, and my loading timesare outrageous. I am in the process of picking out a CPU to upgrade, and I know there are compatability problems.