Where can I download windows xp professional sp3???

Try this link.

https://technet.microsoft.com/en-us/windows/windows-xp-service-pack-3.aspx

You can find XP Pro sp3 embedded in "XP Mode."  See, e.g., https://zeltser.com/how-to-get-a-windows-xp-mode-virtual-machine-on-windows/   Note that when XP Mode is installed in Windows 7 Pro, as intended by Microsoft, it includes a license key and is automatically activated.  It's not clear from these various "how to" guides, but it's my understanding that the embedded license key will not work when you extract the virtual hard disk from the XP Mode download.  A valid retail license key probably will work, although you may have to activate by phone.

The service packs themselves (SP 2 and SP 3) still can be downloaded from the Microsoft Update Catalog.  These service packs can NOT be used to install Windows XP.

Microsoft deleted all download links for XP SP3 from their website.

Very sad and bad and wrong.

I payed for the license.

I understand you don't provide new updates for XP,

but SP3 was an old update and we all  must have the posibility

to download it from Microsoft website.

but SP3 was an old update and we all  must have the posibility

to download it from Microsoft website.

As I said, you can still download Service Pack 3 for Windows XP from the Microsoft Update Catalog.  You must use Internet Explorer rather than another browser.

Go here --> http://catalog.update.microsoft.com/v7/site/Search.aspx?q=xp%20service%20pack

Click "Add" for Windows XP Service Pack 3 (KB936929)

Click "View basket"

Click "Download"