Feedback... and munged disks

Two questions...

1. Each time I boot my notebook computer into Mandrake Linux 7.0, I get a
horrendous screech because the Microphone input and the Speaker outputs
are both turned on to maximum. How can I prevent this?

2. Under Linux, what program do I run to check the hard disk for bad
sectors? (i.e., what's the equivalent of SCANDISK or Norton Utilities)

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