Q: New computer migration

My daughter is getting a new computer.  Hers is a 2009, now running very sluggish, with some issues.  I believe she is running Mavericks or maybe she upgraded to Yosemite.  Sorry, I can't check it right now.

Anyway, the question is what is your advice about her moving?  Should she just start fresh, and just move over what documents, pictures, music, etc…that she really wants (thus, moving it on her own)?  Or, should she just move the entire hard drive?

In the past, I would have just moved the entire hard drive.  However, with the recent changes in the past 2-3 years, it seems like there are some legacy programs on her '09 that won't work here.  Plus, I am certain she has bloat that isn't helpful (perhaps part of her problem with the '09 anyway)….so, maybe just starting fresh would be best.

She is not a hard core user in that she's not making movies or deep into image alteration or using tons of speciality software.