Helping people with computers... one answer at a time.
I want to buy a new laptop. Can I transfer the programs from my Dell desktop to the new laptop, things like Microsoft Office, Windows Media, etc., or do I need to buy this software again?
As with so many questions here, the answer starts with "it depends".
It depends on what you mean by "transfer", and it depends on what the license is for each of the software packages.
You may have to re-purchase some, but I'm guessing that for most, you won't.
First let's define "transfer". If by that you mean "move" - removing the software from your old machine, and installing it on the new - then the answer is typically yes. As long as you have the original CDs to perform the install, or the original downloads, in the case of downloaded software, it's typically quite alright to install the software on your new machine, and delete it from your old.
All that simply relies on the fact that most (though not all) software is licensed to be installed and run on only one machine at a time. It doesn't matter what machine, just that there's only one.
Which leads us to the other possible definition of "transfer". If you mean "copy" - where you would keep your old machine and have the same software installed on both - then you need to check the terms of the license for the software you're talking about. Many, perhaps most, are per-machine. Others, however, are per-location, or per-person, or allow you to install on some fixed number of machines (perhaps 2 or 3), or keep it installed on a machine as "backup".
There are obviously many possibilities, many confusing possibilities, and the only real answer to staying totally legal is to check that license agreement for each software package.
Note also that this only applies to software that you've purchased and that isn't freely available. Windows Media Player, which you've asked about, is a free download, and you can install that on as many machines as you wish. Microsoft Office, even if pre-installed with your computer, is subject to licensing restrictions.
And in all cases, this is one another of the many reasons I strongly recommend you insist on installation CDs for all the software that comes with your machine. If you ever need to move, or reinstall to that same machine, you may simply be out of luck without the CDs. There are PC-to-PC settings and applications transfer utilities out there ... sometimes even drive imaging software can be used to perform this function ... but it doesn't always work reliably. The safest is always a clean install from the original media.