After using a personal computer when I was a sophomore in college,

I was enforced to change many OS, MS-DOS, Windows3.1 Windows95,WindowsNT, Windows2000 WindowsXP,Windows7 (omitting the UNIX system).

However, still, the change of the OS is like "moving".

I think that moving three times in life (about the time of enrollment, employment, marriage) is enough.

However, performances of PC has been promoting dynamically, (it is actually 4,700 trillion times by my calculation). So I also think that it is unavoidable to change the operating system frequently.

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Well, even if I move (change OS), the problem is that you have to "replace furniture".

In this case "furniture" is "application software".

Even though I have to use Microsoft's office series,

A lot of useful tools (Copipe tool, Image size change tool, Draw tool, many, etc.) can not be used at the moving destination with a high probability.

Many of these useful tools are released with good intentions of developers, and most are free (free) and distributed with unlimited (free) distribution.

(To be continued)