How do I completely format my disk?

I want to format because my laptop has stopped connecting to my wireless connection and hopefully this will fix it.

Take a look at this: How to clean a hard drive before reinstall

Placed here for your convenience:

If you refer to a fresh reinstall, when reinstalling you will find several options for the usage of your hard disk drive, which includes but not limits to:

"Side by Side" install, which will install your new OS sharing the hard disk drive but without losing your current installation. This way, GRUB will be updated or installed as required.

"Use the entire disk" which will physically erase the whole disk in order to use all its space for the new OS install.

If what you wish is to use the hard disk drive for a data tasks such as BackUp or other data handling, you can achieve that by first erasing the whole partition and do it from scratch. Formatting the disk will also do the trick.

Several tools will help you to achieve this task in Linux and other OS's.

In Maverick, under "system/administration" you will find a "Disk Utility", inside of which you will find a disk drive and other devices tree on the left and its characteristics and tool list in the right side, where you can find both "Delete Partition" and "Format Drive" options.

You can do this from a Live Session.

A screenshot is placed here for your convenience.

Addittionally, take in consideration that some wireless devices has stopped working as a part of an update from Maverick. That's my case with a Compaq Presario V3000 (V3617LA) which wireless isn't working anymore even with all my efforts and all the web/forums tricks.

Good Luck!