redirection

hello i previously installed kali linux on my acer laptop supposedly as a dual boot but when i turn on the computer it doesn't even show the dual boot it just redirects me to the kali boot menu,if i press graphical install it just restarts the laptop and back to the boot menu and if i press install there's an unknown error on block(2,0) or something like that.i haven't used my laptop for days because of it any possible solutions?( i can't access anything other than the boot menu btw) and please bare with me since im no more than a newbie.