I lost access to my windows 7 drive (Dual-boot windows 7 & Ubuntu). By mistake I compress my windows 7 drive C:\ from within windows. Every time I try to run Windows 7 from my dual boot menu. I get the message: Bootmgr is compressed, Press CTRL-ALT-DEL to restart. I could run Bootrec /fixmbr, diskpart, or attrib to rebuild my MBR table through DOS command windows using my windows 7 recovery CD. The problem I or windows 7 recovery CD cannot access drive C: where is my windows 7 (/Dev/sda1). I get the error message: Cannot open volume for direct access or system cannot find the drive path or drive specified. I still can access all my windows folders and files through home folder in Ubuntu. I relay don't want to reformat and reinstall windows . I come across your website for the use of the DD command, which allow to run DOS commands within Ubuntu, which I did it in basic general to check my MBR record, etc. I am not familiar with the use of the DD commands and how to run the exact command to rebuild my BCD with the codes:

bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd

or compact /u /a c:\*.*

or chkdsk /r /f c:

This is the output of my partitions within Ubuntu with the command:

sudo fdisk -lu

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000d86c0

Device Boot Start End Blocks Id System
/dev/sda1 * 63 910358895 455179416+ 7 HPFS/NTFS/exFAT
/dev/sda2 910360574 972582911 31111169 5 Extended
/dev/sda3 972582912 976771055 2094072 82 Linux swap / Solaris
/dev/sda5 910360576 972582911 31111168 83 Linux

I really appreciated, if anyone could kindly, help code the above DOS commands using the DD commands to fix this issue. I am just not comfortable of doing so for not knowing the exact codes and in the process destroy my MBR and reinstall my both OS allover again. Any other advice to how to fix this issue.

Unfortunately, the dd command in Linux doesn't allow you to run DOS commands. It actually is a direct file copying program (example: if you wanted to make a direct backup of a partition). I would do three things:

1) backup all your important Windows files
2) try following the steps here from the Microsoft forum
3) if that gets Windows working again, fix it back to dual boot by booting from the Ubuntu CD; follow this guide for that.

Best of luck!

Thank you casualfred. I did go through the method at Microsoft forum (I get the above /fixmbr codes) and also using windows recovery CD, but with no luck, I get the same error message: Cannot open volume for direct access or system cannot find the drive path or drive specified. I also, tried boot-repair, bootmed, mbrtool, testdisk, and and DIY data recovery utlity, again with no luck. According to Windows Tech, this is linux issue and should be solved within Ubuntu. This is why, I thought DD commands will be able to so. Any other advice?

How can that be a Linux problem? You refer to BCD in your initial post, are you using the windows bootloader to boot both or did you have Grub installed? My understnding is that the programs needed to repair the mbr are not available on a Recovery disk and you need a full installation CD/DVD. I believe there are programs available to do this which you can download for free.