The first pre-built desk computer we ever bought was a Sony Viao.  It worked so good we ended up getting 2 more.  All of them have been great - no problems after 3 years.  They are well built, quiet, and the cases don't rattle (my Dell at work buzzes so bad sometimes I have to smack it).

Thankfully our IS department has to deal with Dells support.  I did buy a used Dell computer and had the power supply go up in smoke.  At least getting a replacement part was fairly easy - one e-mail and one phone call.  Will see how fast it arrives and if it the right part...

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