You will first have to located the appropriate DVD for Windows 7
Home Premium, be it x86 or x64. That depends on what the sticker on
your laptop says.
x86 - 32 bit
x64 - 64 bit.
The DVD MUST be an OEM DVD, not retail box.
What is OEM?
This is what it looks like.
A white paper packaging over a slim, transparent DVD casing. The
COA is located inside the casing.
You will have to locate this OEM DVD, and not a retail one.
Following that, you will fail to activate Windows, because it's
on a different computer.
You'll have to call up Microsoft and talk to an unknowing Indian
man on the other end of the line to get your new activation
code.
That, or just take the hard drive from your Vaio and transfer it
to your Dell.