Sorry for a late reply but hope my answer will do some help even a little.
If anyone meet similar problem with silviama71 and forgot Windows login password, reinstall the system is not recommended as that way will erase all the data stored on your Windows.
The best way is to try a program called Windows Password Recovery
, you need to rely on another compputer and burn a CD, then insert it back to yoru locked computer. Boot the computer from the burned CD (in BIOS mode) and clear the password. It's quite easy. Best regards.