Hi. You need an operating system disk if you haven't got a recovery disk. Place the disk in drive, on boot up press either F2 or delete. Find boot options, then select cd or dvd as first boot device then save and exit. You computer will start up with the options to format and reinstall windows. Don't forget to back up your work because all data will be lost. You will also need to reinstall drivers, those will probably be on the Toshiba website under support.
chris, June 2009
