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Is it virus-safe to do quick format of hard drive? I want to format disk that was infected and install windows 7 on it, but I am not sure if Quick Format is secure enough. I am aware that it does not delete data but pointers to it, so I wonder if it is possible that virus activates from that data?


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Yes in this case its totally secure. "Full format" is only necessary when you want to erase your data entirely, so it won't get recovered by someone. Like when you sell your HDD. (But in that case you "Secure erase" it, IE. write random bytes on it.)

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I've never seen a virus/worm survive a quick format unless it has installed itself into the BIOS. I would pose the question, however, does it matter? A full format doesn't hurt and only costs time on that one machine.

My advice: If in doubt, full format and get on with it.

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To be precise: there is no real difference, as both are insecure. There are viruses which infect the MBR, which is an area not touched by formatting, be it quick or full. While Windows 95 basically killed off this type of viruses by doing some simple checks for them, running in protected mode and, generally speaking, preventing programs from writing directly to disk, they have made a comeback. Some time ago there was a run of a rootkit that infected the MBR under Windows. If you've got that then you have to boot into a clean environment, ie start from a live-CD or attach the harddrive to another computer, and clean the MBR before formatting the partitions. Overwriting the drive (whole drive, not individual partitions) is another way to accomplice the same.

PS! "Full format" nowadays means "check the disk for inconcistencies", not "clean it completelly". It in no way prevents anyone from recovering the files, it simply makes sure that all areas on the drive are readable. It's simply how drives now work.

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