Greetings.

I have issues when trying to install grub. My pc has two hard disk drives:

1.SATA
Four partitions, /dev/sda1 is for existing windowsxp, /dev/sda2 is another (data) partition, /dev/sda6 is the ext3 i intend to install ubuntu 6.10 and /dev/sda7 is the swap partition.

2.PATA
only one partition /dev/hda1 for data.

The above is the order that my disks are set in BIOS.

The first time i tried to install ubuntu 6.10, when i was asked where to install grub i tried (hd0), which is wrong as after the installation grub didn't show, and windows booted normally. I tried another ubuntu installation, but instead of (hd0) i tried (hd1)...That time grub started up, but when i chose to start ubuntu i got the message

Error 22: No such Partition

and when i tried to start windows i got

Error: NTLDR.sys is missing (not sure about the extension, but i think you are familiar with the error)
Press Ctrl + Alt + Del to restart...

I can't figure out what i am doing wrong! Aren't I supposed to install grub in the mbr of the disk that boots? This disk is the SATA, which is correctly set in BIOS as such...

How can i make grub work? I don't like the solution of unplugging the PATA, installing ubuntu and grub and then plugging in the pata again and coming through all the fuss of mounting it and placing it in the partition tables...

The key here is not how the BIOS sees the drives, but how the Ubuntu installer sees them. If it saw the SATA drive correctly as the first drive, then the GRUB install to hd0 should have worked.

Since you are using the PATA drive for data, you can remove all ambiguity by disconnecting it while you install Linux. (You'll only have to do this once.)

If you have a live CD version of Ubuntu, do fdisk -l before trying to install. This will tell us for sure how linux is seeing the drives.

Finally, be sure you are installing GRUB as part of the linux install (near the end of the process)

If all else fails, download a copy of Super Grub Disk. Dumb name, but it seems to work.

I thought I should try the following:

Install ubuntu on the PATA disk, put grub in the mbr of the PATA, and then put the PATA to boot first...is there a way so that i can make grub "point" to thembr of the SATA disk for booting up windows?

Easy - and Ubuntu will do it all for you anway.
Just do it.

Yes--you have to use the "map" command in the grub config file. (Because Windows needs to believe it is on the first drive)

I don't think the Ubuntu installer automatically creates this configuration.

GRUB manual here

u should read this