I have just spend time on my home pc in my account cleaning out my 'my documents' folder just deleting files etc.

I then went to defragment the c drive on the administrators systems, i left it as it usually takes a while and when i came back to it later there was an error message i cannot remember what it was but i went to restart the system and now i get this message:

<windows root>\system32\ntoskml.exe missing

I think you mean ntoskrnl.exe
not ntoskml.exe .
I have a site where you might go to get you started.

http://support.microsoft.com/kb/103673