Dual booting (windows 7/Arch)

Hello I am trying to Dual boot windows7 and Arch/Linux. My problem is that Grub wont identify my windows install. I think the problem is that I have windows installed on a separate hard drive.

here is my lsblk

sda      8:0    0   1.8T  0 disk 
└─sda1   8:1    0   1.8T  0 part /home
sdb      8:16   0  59.6G  0 disk 
├─sdb1   8:17   0    99M  0 part /boot
├─sdb2   8:18   0  19.9G  0 part /
└─sdb3   8:19   0     8G  0 part [SWAP]
sdc      8:32   0 298.1G  0 disk  /* this is where windows is installed */ 
└─sdc1   8:33   0 298.1G  0 part 
sr0     11:0    1  1024M  0 rom

and this is my 40_custom

###BEGIN /etc/grub.d/40_custom ###
#This file provides an easy way to add custom menu entries.  Simply type the    
#menu entries you want to add after this comment.  Be careful not to change
#the 'exec tail' line above.

menuentry 'Windows 7' {
set root='(hd2,msdos2)' 
drivemap -s hd1 hd2
chainloader +1
### END /etc/grub.d/40_custom ###

If you guys can help me out i will as always be forever indebted

my setup has

insmod part_msdos
insmod ntfs


set root=(hd2,msdos1)

also note, grub counts hard disks beginning at 0, so hd2 is your third harddisk. EDIT: Oh, it is the third harddisk.. my eyes completely skipped your first code entry, lol. msdos2 is wrong though.. partitions are 1 indexed, so seeing as there is only a single partition on sdc, it must be msdos1.

you could also do a search for the harddisk and partition from the UUID

search --no-floppy --fs-uuid --set=root UUID

you can find the UUID from linux:

$ ls -l /dev/disk/by-uuid

best of luck :)