forgot admin pwd windows xp

I forgot my pwd in windows xp
and renamed SAM file and restarted system then the syatem is giving error messge i.e lsass.exe “system account manager initialization failed because of the fallowing error: A device attached to the system is not finctioning. error status:0x0000001. please click ok to shutdown and reboot in to the safe mode”

tn the safe mode also same error

please help me regards.