Hello dezinerite,
Your best course of action IMO is to use the manufacturer's recovery solution that was provided with the laptop when new.
Usually this is a Destructive Recovery and the means to execute the recovery is accessed by a specific keystroke combination at startup, or by starting the procedure within Windows by finding the Recovery Program in your Start Menu>All Programs menu.
Another method which the manufacurers seem to be getting away from, is to run a Recovery Disc provided with the computer when new.
For more detailed instructions it would be best to visit the support pages for your exact model at the manufacturer's support site.
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