Windows Bootcamp Partition quit working

Hi, I just recently bootcamped my computer and started running Win7 on it. Everything worked until last night I was cleaning up some files in OSX, repairing permissions, installed Sophos antivirus software, etc.. Today when I tried to boot into the Win7 it says Insert bootup disk or something along those lines on a black screen.
So I started OSX and looked at the diskutil in which my Bootcamp partition is now labeled disk0s4 and will not mount. I tried repairing and it says:
Invalid BS_jmpBoot in boot block: 000000
Volume repair complete.
Updating boot support partitions for the volume as required.
Error: Disk Utility can't repair this disk...,disk, and restore your backed up files.

When I run the bootcamp utility it says I still have Win7 installed, or rather it gives the option of Uninstalling Win7.

Diskutil Info says the following:
Device Identifier: disk0s4
Device Node: /dev/disk0s4
Part of Whole: disk0
Device / Media Name: BOOTCAMP

Volume Name:
Escaped with Unicode:

Mounted: No

File System Personality: MS-DOS
Type (Bundle): msdos
Name (User Visible): MS-DOS (FAT)

Partition Type: Microsoft Basic Data
OS Can Be Installed: No
Media Type: Generic
Protocol: SATA
SMART Status: Verified

Total Size: 20.0 GB (19999490048 Bytes) (exactly 39061504 512-Byte-Units)
Volume Free Space: 0 B (0 Bytes) (exactly 0 512-Byte-Units)
Device Block Size: 512 Bytes

Read-Only Media: No
Read-Only Volume: Not applicable (not mounted)
Ejectable: No

Whole: No
Internal: Yes
Solid State: No

What is going on here?

I'm running OSX Mavericks, Bootcamp 5.1.2, rEFIT, and Win7.

Thank you very much!

 

When you say Win7 boot disk do you mean the Win7 install DVD?

 

Why would I contact Sophos?.... Is this software known to cause issues with bootcamp? I'm actually uninstalling Sophos right now because it has been making my computer extra laggy and I read that Mavericks has its own maleware and a-v protection already.