laptop Issues, Wont boot????

[Mr-Tamiya]

Hey guys hope soemone can hlep me with this one, I can enter C mos and al is ok but booting up it stops and says invalid system disk, replace and press enter, Now I dont know which operatng system this puter has i think its either 95a or b i have tried boot disks form either and neither worked, the hard drive spins up i can hear that. is there any way to get this thing up and running, it my fiances moms laptop that work gave her but she has no support equipment. any help would be apprecited