ASUS A2500H Sound and Start up problems

Question

Two things.First thing is the old when i start up cant start because either fastfat.sys or isapnp.sys is not there or corrupted however this is only when the computer has not been on for about 4mins then if i turn it off and on again works a treat(also reformated and didnt fix the driver problem).Second thing is the speakers sound blown, thought nothing of this until i tried headphones and they definitly arent blown but they sound it when coming from the laptop so im guessing its the sound card. can anyone help me with this also if you know a site that had pics of how to take the backplate off of this model would be handy seems to be some hidden clips or soemthing.