You may already have a manual for the MSI MS-6549 motherboard, but if not, you can download one at OEM Motherboards Used by HP
You may be able to identify which HP model you have by going to How do I find my product number?
and then clicking on "hp pavilion pcs". If you can locate the number using the information at "HP Pavilion Desktop PCs - How Do I Find the Model Number?" then you can do a driver search at HP using their model number.
There is no information on OEM motherboards, but drivers may be available by HP model number.