Missing a drive partition

I have different scenario, one of my new HD missing while installed window 7. When I retrieved using computer disk management, manage to detect disk but fail to add disk ( as picture shown). Could someone tell me how to solve this problem

I did try, but it cant. A message telling that I unable to continue this process. Attached picture

If you are using Seagate SATA drive, here is

Code:

http://www.seagate.com/ww/v/index.jsp?locale=en-US&name=satatshooterstoragedrivenolonger&vgnextoid=226280b0bf3ea110VgnVCM100000f5ee0a0aRCRD

To download Seagate Tools as follows

Code:

http://www.seagate.com/ww/v/index.jsp?locale=en-US&name=seatools-win&vgnextoid=552bd20cacdec010VgnVCM100000dd04090aRCRD

Hi!
I had win xp, I installed windows 7; so it's greatful:)... but i have missing a drive (around 9 gigas)...
I got the same message than wan3350; with the SeaTools i can do nothing, so how i can solve this?
did wan3350 solve the problem? how? step by step, please; i have very important information there, i need get it...

THANKs

Thanks!
I had winxp in a C766LA COMPAQ; I had two partitions (C, and D (for restore, a system from COMPAQ:10 GG)); so i don't need the extra partition, i wanted more space...
i tried to format the partition with PATITION MAGIC, and then I opened PM, i got error, it was bad... i use partition magic in others pcs without problems...
with the same disk of XP, y format the unit D, so i was great, i had 10 gigas extra, then i installed win 7, and i had a missed drive
i had information in D, i liked win 7, also i need my files...
Sorry for my bad English, im spanish speaker

of course; but i got an error when i select "Change path..."
"The operation failed to complete because the Disk Management console view is not up to date. Refresh the view by using the refresh task. If the problem persists close the disk management console, then restart disk management or restart the computer"
the seatools isnt util only makes test (all are correct)
somebody said a tool called: "Test Disk" but i don't know, it can be dangerous...
I restart my pc, and nothing happens...

THANKS!!

Hello
Had xp on my easynote ; installed W7 - works fine except that my xp drive is nowhere to be seen and the W7 partition is C.Can still see the xp partition in disk management , but cannot add a drive letter ( greyed out ) . Tried to change the W7 drive letter - does not allow me to . Pls help as my xp sp 3 is sitting there somewhere .