hi there, i want to ask u that using killdisk software is safer then format command to harddisk?, if no then please tell me whats safer then format, any software, thank you.

Safer than Format? Format isn't a dangerous command if what you're trying to do is wipe everything off of your hard disk partition. The "worst" thing that it can do is wipe everything off of your hard disk partition! What do you want to do?

i want to know that if i format my hdd many times, it causes bad clusters, but if i do killdisk , it would not creates a bad clusters, is this right?

I'm not aware of any problem with formatting a hard drive too many times and causing bad clusters.