Trouble with computer boot up and sound

For a while now, I've been having a lot of trouble with my Dell laptop. The sound is stuck at 100% all the time, so I have headphones plugged in to stop it blaring any sounds at top volume all the time. In addition, my scrolling is completely broken and I have to use the arrow keys. I have checked settings for both of these issues, but cannot seem to fix them. On top of this, nearly every time I turn my computer on it goes to a 'diagnostic boot' that doesn't ever find any problems but does make a lot of loud beeps and disturbing noises. I also cannot move between windows by hovering over the chrome icon; the windows simply don't pop up.

For the past few weeks, these issues all went away with no explanation (except the scrolling issue) but just returned for no reason. I don't know if these are all separate issues or interconnected from a virus or something. Please help! The startup noises have been getting me in trouble in class, and it's making my computer really hard to use. Thank you.