You can connect multiple computers to one monitor using multiple Inputs and cables. And mostly "migration software" doesn't work very well. There is a section here in how to migrate your data to a new computer: [URL]
I have an existing XPS and have purchased a newer one. Buying the tower only to use with my existing monitor. I have read through articles explaining the steps in the migration process and it seems like I need to access both computers throughout the process? How can I go about this if I have only a single monitor?  I do have access to a laptop, can its display be used with one of my towers?
Migration tool - how to use with one monitor