is there any way reset the Mass Memory to exactly as it was out of the box...?

or is it safe to format the Mass Memory, will i lose/corrupt any installed applications?

If you format the mass memory, then everything on it (including apps you've installed there) will be gone.

There's no easy way to reset the mass memory to what it had when the phone left the factory, unless a complete, original mass memory image (copy) is made available (or the individual pieces of content that were on it originally).