Hola, He probado la herramienta de sysinternal autorun, he deshabilitado un registro y ahora no arranca el portatil, tenia ccleaner instalado puedo utilizar el backup del registro para reparalo? también tengo un cd de instalación de windows 7 pero es de 32 bits no se si sirve....
Gracias de antemano por vuestra ayuda
Ya lo he conseguido por si a alguien le sirve he hecho esto
1. Identify the correct drive letter for your Windows installation. It could be a drive other than C: but it won't be X:. You do it by typing the commands
    dir C:\Win*
    dir D:\Win*
    dir E:\Win*
    until you find the Windows folder.
    I will call that drive "Q:".
2. Type these commands:
    cd /d Q:\windows\System32\config
    xcopy *.* Q:\MyRegBack\
    cd  RegBack
    dir
3. Examine the dates of the Software, System and SAM files. Were the files created before or after your problem became apparent?
4. If they were made before the problem became apparent then you can type these commands:
    copy /y software  ..
    copy /y System  ..
    copy /y Sam ..
    (the two dots are part of each command)
5. Reboot normally. If things do not work out then you can backtrack by copying the original registry files from Q:\MyRegBack to Q:\Windows\System32\config.