my son had a computer virus and he used killdisk to erase his hard drive on his laptop, now we cant do anything with it, his laptop is a toshiba satelite 2100cds, when we switch it says missing operating system, i have tried various boot discs but nothing works when i try to install a new os ie:win xp i get a message saying this program cannot run from ms dos any help please

Peter

Is this Toshiba Satellite 2100CDS fitted with an AMD 400MHz processor, a hard disk of about 4Gb in size and only about 32Mb RAM? If so, don't try putting Windows 2000 or XP on it - it won't be able to manage it. The Windows 98 that it came with will be just fine on a laptop like that.

Did you get a recovery CD with the laptop? If so, you ought to be able to put the CD in, then boot up with that in order to run the recovery process or format the hard disk and get Windows 98 installed.

Failing that, get a Windows 98 or Windows 98 SE boot disk from BootDisk.com - http://www.bootdisk.com/bootdisk.htm

When the laptop successfully boots off of a floppy disk, run fdisk and choose the option to delete a partition, followed by the primary DOS partition.

Exit Fdisk and then reboot off of the floppy again. Run fdisk again and, this time, create a new partition (a primary DOS partition) and tell it to use all of the available space.

Exit fdisk and then reboot off of the floppy again. At the DOS prompt, type format c: /s

This will format the whole hard disk as a new C: drive, wiping anything that used to be on there.

Then, when that's finished, reboot off of the floppy again. Put in the Windows 98 install CDROM. At the DOS prompt, type cd e: and press Return. The DOS prompt should change from A:> to E:>

Type setup and press Return. This should start running the Windows 98 or 98 SE installation from the CDROM.

Let us know if that sorts it