Apps deleted on Haier mini laptop

Some time ago i noticed the apps on my laptop started disappearing, i did not think of it as a big issue as i thought it might someone in my house doing it but as time passed all of my main apps like setting, ms excel, powerpoint etc are gone i cant search for them and when i somehow open them it shows like app not found or something, i dont know if this is like a virus or its a windows issue so someone help plz