I followed this guide http://www.youtube.com/watch?v=6r3czVPTmoo now it still try loads grub boot loader and gives me error 5 and i can't do anything my laptop is useless can someone help me please.

If you deleted the partitions but the bootloader gives an error, it is likely because the bootloader points to a file in a non-existent partition. A new installation of some OS or a wipe of the boot track will clear that. The installation will create the partitions and files you need and will install a new bootloader. If you wanted to delete GNU/Linux completely, you need to remove/change the bootloader as well as the partitions.

dd if=/dev/zero of=/dev/hda or sda will erase the whole drive, not just the partitions but also the bootloader. A full-surface write is also a check of the operation of the disc. If you get no errors, the disc is OK.

ok thanks but how i install another os system if i can't do any thing other than watch it tell me error.

Do you already have another system installed on the HD and do you want to continue using it?

If you have no system at all, then (re)installation makes sense. If you have a system, then the best thing to do is fix up the mess so that the system can boot and you can access all your files again.

Boot from the installation CD before it tries to boot from the hard drive. You may need to set the BIOS boot order to CD before Hard Drive.

Go into bios (setup) when first booting the computer and set the boot order to boot from the optical drive before the hard drive, stick a CD/DVD of the OS you want to install into the optical drive and re-boot. If you set it up right the computer should boot the OS installation CD/DVD instead of trying to boot something off the hard drive, thus eliminating the grub error.

Install from CD (or other bootable external media)

i have windows vista already installed

i am in the boot order how do i know wich one is the optical drive is it cd/dvd: pioneer dvd-rw dvr-k17rs-(

Which ever one you want to use, normally I use the ROM drive (cd/dvd) and not the burner (rw). If you're still not sure, pick one and see if the computer boots the CD, if is doesn't, try booting it with the other optical drive.

either:
1) Boot from Windows CD and fixmbr (google).
or
2) reinstall grub with chainloader menu option (google!!).

If you have Linux LiveCD then:

1. boot from the CD

2. make a copy of the HD's bootsector - for example, if the HD is /dev/sda then:
dd if=/dev/sda of=bootsect.bak bs=512 count=1
Make sure you make another copy of that file somewhere safe (like a USB stick); if you accidentally damage the MBR you need the unaltered copy to restore things to the not-so-broken state.

3. Kill the "magic number" which the BIOS uses to identify a boot block:
dd if=/dev/zero of=bootsect.bak bs=1 count=2 seek=510

4. Copy the altered bootsector back:
dd if=bootsect.bak of=/dev/sda bs=512 count=1

5. run 'fdisk' and set the Winduhs partition as 'bootable' (if it's not yet marked bootable). You can check what partition is marked bootable via:
fdisk -l /dev/sda
The bootable partition will be marked with '*'.

Once that's done you should be able to just boot straight to VisDuh; the VisDuh partition should still have its boot code.