I have a laptop. scavenged from college and I want to. clear all the old se?

It's a scavenged computer, so we can assume that there is nothing that you may want to keep.

Just pop in any operating system install disk (it can be Windows or any Linux distro) and do a clean install: Format the drive and install the OS.
You'll get a partitions manages step. In it, suppress any existing partitions.
Create the required primary partition.
Optionaly, create a second partition for the data.

Electro
August 2012

just replace the hard drive and install a new op system

mm
August 2012

Its rather broad question. If it has a hard disk password, you'll need to fit anew hard disk and then install an Operating System e.g. Windows and Applications from scratch.

If it has a hardware password, some can be recovered and some can't- it dends on the laptop and you don't say what it is.

If it has a Windows password, you need to reinstall Windows and any Applications from scratch.

T
August 2012