is there any software for finiding bad sectors on hardisk
All major OS always has at least one such software. Windows 9x had ScanDisk. Windows NT based (Windows NT/2000/XP/Vista/7) has ChkDsk.
Open My Computer -> right-click on drive you want to scan -> Properties -> Tools -> Check Now
Check both of check-boxes hit the Start button. If that partition is in use then Windows will inform you that do you want to ChkDsk at boot. Select Yes and restart computer.
Remember to check both of check-boxes.
I also recommend to use OS builtin utilities for such tasks because your OS knows the best about its file systems.
You can also boot from a linux live cd and run the bad blocks command. Something like badblocks /dev/hda. See man badblocks for more info. The advantage of badblocks is that you can check hard disks before you install an OS on them.
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