I've seen computers in the shop every 3 months because "a friend" told a 1USA customer to defrag the hard drive every morning at 3am.
This is simply not true.  In fact, in my humble opinion, it makes the computer run slower and CRASH more often.

A hard drive is like an old LP Record, but records from the inside tracks to the outside tracks.  The terminology is "Hard drives have tracks and sectors, and a few heads (like the old LP Record Players)"
First, the heads go to the Index section of the hard drive - called the File Allocation Table... which tells it which tracks and sectors that your file is on... then it goes to those tracks & sectors and gets your file.

On a new (empty) hard drive, first Windows is installed... then all the WindowsUpdates... then the Anti-Virus software... then some programs.  They are already in the optimum tracks & sectors.
Then as you use the computer, it will store documents, music files, temporary cached web pages and all kinds of temporary stuff...
So... in defragging the hard drive... you would be moving Windows components and all the good programs... to make space for ! temporary files !?
I have no idea why you would want to move the good stuff in the first place.

So my recommendation is:  Get the new computer, install Windows, the WindowsUpdates, MS Office, OpenOffice or other large programs... THEN do the one-and-only Defrag on the hard drive.  I see no need to move the good programs to make space for temporary programs.

There are other, better, ways to keep a computer clean of 'temporary files'.

BarryZ