How can i recover bad sectors in my hdd drive using a startup disk?

Let's try to explain the question that grinds us all when in cams about the hard disk. Can we actually repair a bad block? Before of the answer you must find some information about what is a hard disk, how does it work, what are bad blocks. After that you must identify them because you will need the exact location of the affected sectors. After you have done that you must run a few steps:
- before you try to resolve the problem with the bad sector you must extract the data that was written to that block. To do this you must run a Recovery program that you can find freeware on the net.
- bad sectors are unreadable parts on your hard disk but the nature of them must not be always physically and that part of the platens to be destroyed. The bad sectors can be simulated by some programs. This means that some programs installed on your computer can interrupt the reading process on to another segment of the platens. That is in the most happier cases but the chances that the bad sectors are cause by this is less then 10 percent. In this case is difficult to resolve the problem because even the Scandisk or other identification programs used to discover bad blocks will give a rapport that nothing is wrong with your hard disk. The best way is to uninstall the latest programs applied to the computer.
- lets supposed that you have a 20 gigabits partition on your hard disk that has bad blocks. After the identification program it will indicate you where are the blocks situated on the partition. So this way you can isolate them in to another partition that you must never use again. Another scenario can be created and the bad sectors can be at the beginning of the partition in the middle of it and at the end of the partition. Know it's a little bit tricky because you can't just go on and create three new partitions to eliminate the bad sectors from use. In this case most of the new hard disk has a spare space available just for this type of scenarios. You must access the CASH memory of the hard disk and indicates to the hard disk that instead of writing down on the effected blocks it must write to the spare blocks.
- another to restore the hard disk is to use the low level format option. Many of you think that low level format is a program. Wrong, the low level format option is set for any BIOS and can be easily use if you know some command line programming. The low level format can take to be complete a very long period of time but in the most cases we can obtain marvelous results. Actually the low level option takes every cluster of the hard disk and identifies them again (throw a thermal process) and writes down on the memory of the hard disk what sectors can be written and witch blocks are un-writable. This procedure is the best that can be because it will need no effort from your side to try and avoid the bad blocks that already exists and the hard disk itself know where the bad blocks are.
In conclusion the bad blocks can't be fixed. The problem is a permanent one and we can only try to use the hard disk until it is broken down for good. But if you are having financial problem this is a best way to keep going with your old hard disk.