The quickest and easiest way would be to create a GEDCOM file of your data in PAF3 on your old computer, save it to a diskette. Then import that GEDCOM into PAF5 on your new laptop.
You could also copy your PAF3 data onto a diskette, if it will fit, then copy that data onto your laptop. When you then start PAF5, click FILE|NEW. Create a new database in PAF5 of the same name as you used in PAF3, e.g. "pinson". Again, click on FILE then OPEN. Now go to the data you moved on to your laptop - locate it in the window that opens - click OPEN. PAF5 will then ask if you want to convert the data - click YES. Your data will then be opened in PAF 5 format.