Help to format HD with too many bad sectors

This notebook started to behave badly and I found that the problem is the HDD. It took me about two weeks, a bunch of apps and a lot of patience... I found that I need to replace the HDD. But I want to try one last move... and wish you guys here can help me.

For you to get the scenario: I first ran the Windows native disk tool and it reported no problem. But the system was still slow and freezing.

So I made some googling and ran Check Disk GUI, but it couldn't complete its job. So I started to figure out that the thing was a bit harder than I first thought.

I tried to defrag and optimize with Auslogics Disk Defrag Portable, and it too couldn't go all the way.

I tried PartitionGuru, which, finally, could do the job – in more than 48 hours of disk scan! And it reported: "Disk verify completed. 548 bad track areas found."

After all that, things went worse: I couldn't start Windows, I got a "Missing operating system" message...

Then I tried Wondershare LiveBoot 2012 to no avail.

The last effort I want to try is use some portable app (running from a USB pen drive) to format the whole HDD.

The HDD in question has three partitions. C: (system), D: (data, I created this partition), and a hidden one that keeps the data needed to restore the Acer notebook to its factory settings.

If I succeed to format the whole thing, I'll try to make a fresh install of Windows 7 Home Premium. I want to format the whole HDD (from a USB pen drive) to have one single partition.

Would you please tell me which app I can use to do that?

TIA.

Disk - Clean and Clean All with Diskpart Command
Be aware there are two types of disc errors
"soft errors" are bad sectors that can be written out leaving the rest of the disc usable
"hard errors" are more serious and cannot be overcome
when errors are detected its a sign to get a new disk, even if you get it running again can you ever really trust it, generally its only a matter of time until it gets worse or gives up totally and given you have over 500 errors it dont look good !

Considering that I can't go beyond the "Missing operating system" message, do you think this Delete All Partitions action with PartitionGuru will do what I want?