VMDK's just vanished

My server crashed the other day and after restarting esxi, the 2 data stores are missing all 4 vmdks

this pic shows the hard disks (vmdk's) 2-5 present

pic2 shows that they are no longer represented by a *.vmdk file..   The vmdk that exists in pic1 is no longer available to add

I suppose i need to interorrgate the data stores someway or another, any ideas,

thanks in advance