I can help. First let talk about installing it. It is very easy. Select a bay directly under or over the current hard drive. I am assuming it will be a slave(secondary) drive. Now that you have a bay end mind, lets configure the drive. If it will be the only drive it probably is already configure as Master. If it is the second drive configure it as Slave. There is a series of pins between the IDE socket (where the flat cable will plug in) and the power socket (it has four larger pins). On the face of the drive is a chart showing how to configure these pins. Set the jumper to what fits your needs.
When plugging in the IDE cable there is a red dotted or solid strip on one side of the cable. It should be closest to the setting pins/power plug. The power plug is keyed and should only go in one way.
Insert the drive into the pre-selected bay and secure with th screws. In reality one screw should do but put in as many as you can. If you have a Compaq it may have "quick rails" inside the case to attach to the drive to make it easier to install.
That should cover the installation.
The easy way to clean that disk would be to download Active@KillDisk
and run it several times. This will destroy any virus' that may be on that drive. I would run it 3-4 times, but most would say once is over kill. If you are using ME again pop in the CD and boot the computer. Follow the on screen instruction. If you are using W2k or XP it will be the same proceedure.