I'm surprised that you can boot with your manufacturer provided disks. Have you check the BIOS settings to make sure your computer boots from the CD before the HD? A lot of work machines are setup this way, to keep people from messing around.
When you boot in, use the repair system option. If that doesn't work, you'll have to boot into the system recovery console. To get to the recovery console, you can select the option under repair my system, or press F10 while in the setup.
Use the following command to fix your MBR in the recovery console:
d:\boot\ bootsect.exe /nt60 all
Here is the official Microsoft link. I'll cut and paste it, but the formatting isn't gonna translate.
You can use the Bootrec.exe tool in the Windows Recovery Environment
(Windows RE) to troubleshoot and repair the following items in Windows
Vista or Windows 7: A master boot record (MBR) A boot sector A Boot
Configuration Data (BCD) store Note When you are troubleshooting
startup issues by using the Windows RE, you should first try the
Startup Repair option in the System Recovery Options dialog box. If
the Startup Repair option does not resolve the issue, or if you must
troubleshoot more steps manually, use the Bootrec.exe tool. Back to
the top MORE INFORMATION To run the Bootrec.exe tool, you must start
Windows RE. To do this, follow these steps: Put the Windows Vista or
Windows 7 installation disc in the disc drive, and then start the
computer. Press a key when you are prompted. Select a language, a
time, a currency, a keyboard or an input method, and then click Next.
Click Repair your computer. Click the operating system that you want
to repair, and then click Next. In the System Recovery Options dialog
box, click Command Prompt. Type Bootrec.exe, and then press ENTER.
Note To start the computer from the Windows Vista or Windows 7 DVD,
the computer must be configured to start from the DVD drive. For more
information about how to configure the computer to start from the DVD
drive, see the documentation that is included with the computer or
contact the computer manufacturer. Back to the top Bootrec.exe options
The Bootrec.exe tool supports the following options. Use the option
that is appropriate for your situation.
Note If rebuilding the BCD does not resolve the startup issue, you can
export and delete the BCD, and then run this option again. By doing
this, you make sure that the BCD is completely rebuilt. To do this,
type the following commands at the Windows RE command prompt: bcdedit
/export C:\BCD_Backup c: cd boot attrib bcd -s -h -r ren c:\boot\bcd
bcd.old bootrec /RebuildBcd /FixMbr The /FixMbr option writes a
Windows 7 or Windows Vista-compatible MBR to the system partition.
This option does not overwrite the existing partition table. Use this
option when you must resolve MBR corruption issues, or when you have
to remove non-standard code from the MBR. /FixBoot The /FixBoot option
writes a new boot sector to the system partition by using a boot
sector that is compatible with Windows Vista or Windows 7. Use this
option if one of the following conditions is true: The boot sector has
been replaced with a non-standard Windows Vista or Windows 7 boot
sector. The boot sector is damaged. An earlier Windows operating
system has been installed after Windows Vista or Windows 7 was
installed. In this scenario, the computer starts by using Windows NT
Loader (NTLDR) instead of Windows Boot Manager (Bootmgr.exe). /ScanOs
The /ScanOs option scans all disks for installations that are
compatible with Windows Vista or Windows 7. Additionally, this option
displays the entries that are currently not in the BCD store. Use this
option when there are Windows Vista or Windows 7 installations that
the Boot Manager menu does not list. /RebuildBcd The /RebuildBcd
option scans all disks for installations that are compatible with
Windows Vista or Windows 7. Additionally, this option lets you select
the installations that you want to add to the BCD store. Use this
option when you must completely rebuild the BCD.