Data files can be transferred by copying to a removeable media (floppy, CD, pen drive, ZIP, etc).
If you made the file, you "own" it and can legally do anything you want with it. If someone else made the file (e.g., a program), then some license controls what you can do with it.
Note that most modern programs can not be transferred by a simple copy. Forgetting legal issues, copy&paste simply will not work. They must be "installed", usually from a CD, sometimes from an EXE file that you get via a download. If you do not have the CD or the original installion EXE, then you can not move it.
If you have the installation CD it probably contains a license agreement (e.g., license.txt, or readme.txt, or maybe an html file, etc). If you can find the license, it should tell you whether you can install on only one PC (common), or multiple PCs (rare), and whether you can transfer it from the old PC to the newer one (sometimes allowed).
License agreements can often be found on the website of the software vendor. Or, you could contact their sales or support group.
In the event you do not have original CDs or EXEs, or have a non-trasnferable licnese, you still might be able to get a discount on a new licnese by proving that you already own a license on another PC. That is, many vendors offer discounts to previous customers. It is worth asking. Also, some vendors will offer discounts, if you currently use a competitor's product. Further, some software is regularly sold at discount or with rebate. Check local PC stores for weekly specials.
Finally, for many programs there are free alternatives, which might serve your needs. Probably not likely for something like QUICKBOOKS, but there are free Office Suites, antivirus, image processing programs, CD writing software, etc. Some are actually quite good. If you are interested in looking into freeware, start with the following websites. However, note that some programs listed are shareware, meaning they can be installed and tested, but will stop working in a fixed time or have some disabled features.http://www.majorgeeks.com/
look near top left for "FILES", then by category under that word.http://freewarehome.com/http://www.filehippo.com/http://www.thefreecountry.com/http://www.all-freeware.com/http://www.openoffice.org/http://audacity.sourceforge.net/http://www.ccleaner.com/http://www.freshdevices.com/index.html
free, but requires registration (i.e., email address)http://www.irfanview.com/