Archive/Install or Erase/Install?

Why do you need to do this? An archive and install probably would be the easiest if you are not experiencing any issues currently and just want a new root system. Secure erase is not necessary unless you are reselling or giving your Mac to someone else as you will eventually rewrite information over the blocks that used to hold your data.
The tech was probably booting into single user mode. Boot holding cmmd-s but if ou don't know unix you probably should not muck about. You can also see all processes with Activity Monitor.app in Utilities or open a shell and type:
top -a

 

I do an erase/install every couple of years. It really does give you back a snappier machine and allows you to get rid of all the junk files that accumulate. The best setup is to have a 2nd drive dedicated as your OS/Applications drive (like as SSD) which allows for a quick and painless erase/install without touching your own user folder that contains all your documents/files.

 

They were probably running in single user mode or verbose mode that just gives them the they info behind the spinning logo at start to show how the system is responding.

Not much you have to worry about, but to get the best performance you can drag and drop your iTunes library folder to an external drive and do either the archive and install or ease and install then just drop the iTunes library back onto your macs main hard drive and you can pick up where you left off.
You may even benefit from getting a larger external drive and just keeping the libraries off the main internal Mac drive to possibly keep the main drive optimal in performance.

 

What system are you using? Those install methods kind of went obsolete.

If you have something slowing down your system you need to find the problem and deal with it. Reinstalling the system might get you there, if you're lucky, but it's like replacing an engine because the spark plug was bad.

Rob

 

I should have clarified specifically why I always do a clean install every couple of years or whenever a new OS is released: As a final cut pro user for many years, the first thing anyone will ask you if you come across issues with the program, after a new OS has been installed, is: "Did you do a clean install?" In the vast majority of cases (unless there is some kind of hardware failure, memory corruption etc) this will solve the problem (at least in my experience)... Whether or not it is necessary with Lion... I really don't know. I just continue to do it out of habit.

 

Then backup your user files to extra HDD. Boot to OS X disk or disc and re-format your hard drive. Install OS X fresh on new partition. Create account with same name as previous system (helps minimize permissions issues) Move over your user files. Patch everything, repair permissions and you are done.

 

Zero out the drive, and then reinstall it.