If you still have use of Windows use "Disk Manager", right click on the other partitions and delete them, then right click on the existing partition with Windows and choose to extend the partition. IF you can't use the Laptop at all, you will need to install the HD in an external enclosure on another computer and use Disk Manager to delete all the partitions, even small boot partitions. You should have a completely un-formatted disk with no partitions. Do not Format it. Then you can re-install it in the Laptop and do a clean install of Windows. The Windows install disk will automatically format the HD for you at the time of installation and the Laptop will be like day one. You may need to install some drivers, like the Lan driver...