Diskpart error

Hello,

my problem is that w7 can't boot. I found that i can repair that in command prompt on w7 boot CD, and if (when i enter repair window) no installed windows appear i need to do the following:
in the command promp:
bootrec \fixmbr
bootrec \fixboot
bootrec \rebuildbdc

and if I got an error (which, ofcourse, i have) i have to enter diskpart
i did with the following:

list disk
select disk 0 (which is the only one i have)
list partition
select partition (and here is the problem (on every partition));
i got this message: virtual disk service error:
this operation is not allowed on an invalid disk. The disk may be invalid beacuse it is corrupted or failing, or it may be invalid because it is offline.

My question is: what does this mean and what i have to do so my w7 would start, and if there is possibilty that i can save my data from this hard drive.

thanx

Please see the suggestion at your other post. There you mention that you are concerned about recovering your data.

For this post, I'd suggest these free, bootable diagnostics:

H/W Diagnostics:
Please start by running these bootable hardware diagnostics:
Memory Diagnostics (read the details at the link)
HD Diagnostic (read the details at the link)

Click to expand...