Copying programs and files after format

Hello there!

A friend of mine got a computer with an illegal version of Windows XP. For his company he needs a connection between his computer and his PDA, but that doens’t work because of the illegal version. I got for him an official version of Windows XP pro.
I want to install the legal XP version and format his old. Offcourse there are a lot of import files and programs on his computer.
I know files and drivers can be easily transferred onto an external hdd. However, he has important programs on his pc, who have adapted databases and stuff. But some other tools are also interesting for transferring.
I have already encountered some problems in the past by copy-pasting the folder from program files into the new created program files folder.
So my question is, if it’s possible to copy programs onto the newly formatted version, and if so, which files/folders should I check of copy aswell to make the program work?

Any other tips to do this pretty fast without having to reinstall everything?
Could this be an other option: partioning the c:/ drive in c and d, and install the legal XP on the D:drive, then afterwards, copy all the files(program files/folder/files…) from the c-drive to the d:/drive . And after that is done, just undo the partition and make 1 big drive again? Is this an option? Or too hard to pull off?

Thanks in advance!
Kind regards
Maxx-iT

Depending on the situation, he can either attempt to change the CD key with a 3rd-party tool (this only works if the installed version is the same as the CD you bought him–such as OEM or Retail), perform an in-place upgrade, or perform a repair install: http://www.michaelstevenstech.com/xpfaq.html#018

I have already encountered some problems in the past by copy-pasting the folder from program files into the new created program files folder.
So my question is, if it’s possible to copy programs onto the newly formatted version, and if so, which files/folders should I check of copy aswell to make the program work?

You can’t copy a program from one place and paste it to another. There’s simply no easy way to get applications to run like that–there are too many things that happen with the registry and application data folders buried in the user profile when a program is installed. You will simply have to install them. It’s not just about the files sitting in the program files folder.

Any other tips to do this pretty fast without having to reinstall everything?

Not really. You could possibly look into unattended installers, but that takes more time to research than it does to just proceed with the installation (it’s only really useful if you tend to prep more than one workstation). It really only takes a day or so to fully prep a workstation.

You could also see if these applications have a “backup” option. You might be able to back the application’s settings, and restore them when it is reinstalled.

Could this be an other option: partioning the c:/ drive in c and d, and install the legal XP on the D:drive, then afterwards, copy all the files(program files/folder/files…) from the c-drive to the d:/drive . And after that is done, just undo the partition and make 1 big drive again? Is this an option? Or too hard to pull off?

Nope, there are several assumptions you’re making that prevent this from working. You can’t copy & paste applications. You can’t change the drive letters of an operating system. If you install an additional operating system and want to delete the first one, the partition has to stay (although you can usually delete most of the files and shrink the partition–some files need to remain behind in order for the second operating system to boot properly).