Don't bother with MBRfix, it's for advanced users only.
Hiren's has a tool called "Bootfix Utility". I think this is more for you. I can't find bootfix utility at a reliable place elsewhere so you should download the whole of Hiren's BootCD and select "bootfix utility" from the "MBR Tools" section and use it.
If you try to download some of the tools from Hiren's individually, you're most likely going to end up with a German language version or a virus or something. Some of them are discontinued so they're hard to find from a reliable source.