I had a MS tech help me about 1 and 1/2 years ago with a problem loading an update.
He told me that MS was soon to stop servicing SP2 and he managed to get SP3 to load on my old system.
Earlier SP3 wouldn't work with my Realtek sound system, but after the update to SP3, we reloaded my original Realtek driver and then did update from Realtek. So it works now.