Need help with a disk read error occured Bootcamp and Win7

This is a list of unrecoverable partitions. Press Return to Continue and you should a list of recoverable partitions.

Based on this Testdisk output, the most likely candidate is

Does the size of 930Gb look correct? If it does look reasonable, scroll down to the MS Data at this NTFS Start and use 'P' to list files.

You should see something similar to the following...

Yes, that is what we are looking for.

Install GPT Fdisk (aka gdisk). Leave your Testdisk display and start a new Terminal Window. You need to use the following steps. If you see any error messages during the following steps, please stop and post back here with the error message. The following steps have values from your Testdisk output (and you can verify) in Steps 7 and 8. Please notice the'+' sign in step 8 (this is called offset notation). The text in parentheses is for informational purpose to describe the action being taken. Gdisk has one-character commands except when entering numbers.

Rebuild GPT4 using start/end offsets

1. Sudo gdisk /dev/rdisk0
2. P (print the full list of parts)
3. D (delete)
4. 4 (part 4)
5. N (new part)
6. 4 (part 4)
7. 1954805760 ( - Start offset in sectors or the start point for Bootcamp part)
8. +1952223225 ( - Size offset, as opposed to End offset)
9. 0700 (Windows part type)
10. P (print list of all parts just to see what changes will be made)
11. W (Write the new GPT)
12. Y (Yes! really write the new GPT)

This will delete and re-write the GPT partition info for /dev/disk0s4.

Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see sample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A at the end of the steps

1. Sudo gdisk /dev/rdisk0
2. P (Print list of parts)
3. R (Recover)
4. O (print current Hybrid MBR)
5. H (chooses Hybrid)
6. Partitions numbers to be hybridized: 2 3 4
7. Y (Good for GRUB question)
8. N (part 2 boot flag)
9. N (part 3 boot flag)
10. Y (part 4 boot flag make NTFS bootable partition)
11. O (print current Hybrid MBR)
12. W (Write the new MBR)
13. Y (Yes! write the new MBR)
14. Reboot

Here is sample Q&A for this section. Please notice the Press Enter/Return.

Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)

Enter an MBR hex code (default AF): Press Enter/Return

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #3 (MBR partition #3)

Enter an MBR hex code (default AB): Press Enter/Return

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #4)

Enter an MBR hex code (default 07): Press Enter/Return

Set the bootable flag? (Y/N): Y

Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

Please post the output of GPT and FDisk commands. You may need Windows Startup Repair.

Can you post the output of the Fdisk command?

Your GPT and MBR are correct. Can you run Windows Startup Repair using the original installer (USB or DVD)? You can re-build the USB installer using BCA again, if necessary.

If you iMac has a built-in Optical drive and it was originally used to install Windows, the following steps should bring the up the installer.

1. Insert your W7 DVD in the Optical drive.

2. In System Preferences -> Startup Disk -> select Boot Camp (no the DVD) -> click Restart.

3. This should bring up the Windows Installer. The images should look similar to the ones shown at http://imgur.com/a/1DaOE#0 .

4. Select Repair.

5. If Repair fails, you may have to get to the Command Prompt and use bootrec.exe. Please see https://support.microsoft.com/en-us/kb/927392 .

If your Mac allows creating a USB Installer (2012 and later Macs) from Windows ISO/DVD, you can use BCA to create an installer and use the USB installer instead of the DVD in step 1.