I have reconstructed your MBR by extracting an MBR template from Vista's winsetup.dll file, and then patching in your partition table and disk signature bytes:
http://www.users.on.net/~fzabkar/temp/JanJanowski.mbrAssuming Vista gives you full access privileges, you could write this 512-byte file to sector 0 of your physical drive.
In DMDE, select your physical drive and choose Mode -> Hxadecimal.
You should see two text strings, "MBR Error" and "ress any key to boot from floppy". This will confirm that you are looking at Seagate's MBR code.
Now choose Tools -> Copy sectors.
In the Source tab choose File and then navigate to JanJanowski.mbr. The Start Position, End Position, and Source Size fields should now contain 0, 511, and 512, respectively.
In the Destination tab, select Device, choose your physical drive, and then choose 0 for the First Sector and 1 for the Number of Sectors.
When you click OK, you will be restoring your original MBR code to LBA 0 of your boot drive.
However, before you embark on this path, you should satisfy yourself that this procedure is OK. To this end I would first try a harmless edit. For example, you could change "MBR Error" to "MBR error", then reboot and confirm whether the change has stuck.
