OK I will need to try and locate some files and see if they are in the right place
Prior to this problem what happened ? Were you running a malware removal programme or something like that ?
If this fails I may need to run a programme from a USB drive to locate and then run one of your system restore points - do you have a USB drive ?
Run OTL and copy the following into the custom scans box and then press run scan
/md5start
lsass.*
/md5stop