Aaron,
I don't know if Ulead handles web purchases differently in the UK, but here (in the U.S.) rather than provide key codes to activate the trial version, they email a list of download links for the FULL version of the program & additional content.
The recommended installation procedure is to uninstall the trial, delete the trial program folder (if it remains), clear your cache, and then install the "full" version. If by chance you have installed the full version "over" the trial, this may be responsible for some of the problems you're having including the serial number issue. If this is the case, I would consider a clean install following this procedure (at your own risk) as closely as possible:
1. Launch Windows Explorer and go to tools\folder option\advance setting to check "show hidden files and folders".
2. Please clean first your hard drive: Go to Start>All Programs>Accessories>System Tools then click Disk Cleanup. Choose the system drive to clean (ususally drive C then click OK. Check all boxes for cleanup and then click OK to clean your hard drive.
3. Go to your Add/Remove Programs in Control Panel and remove/uninstall PictureShow 4.
4. Go to "C:\Program Files\Ulead Systems"
5. Delete the folder for CD & DVD PictureShow 4.
6. Delete "C:\Program Files\Common Files\Ulead Systems" (***please don't delete if you have other Ulead programs installed)
7. Go to "C:\Program Files\InstallShield Installation Information". Delete the folder "{1F6199F9-9BED-4B43-9E5C-8495086EE714}"
8. Click Start: Run: type "regedit", click Ok.
- Under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\, please delete
{1F6199F9-9BED-4B43-9E5C-8495086EE714} folder if they are present
- Under HKEY_CURRENT_USER\Software\Ulead Systems\,please delete Ulead CD & DVD PictureShow 4 folder
- Under HKEY_LOCAL_MACHINE\Software\Ulead Systems\,please delete Ulead CD & DVD PictureShow 4 folder
9. Close regedit.
10. Install full version of CD & DVD PictureShow 4 again.
11. Install extra content.
If all goes well you should now have a serial number in the "about" screen and perhaps the other problems you've experienced will be resolved as well.
If the above doesn't help I would recommend that you email UK Customer Service and request a serial number which you can then use to complete your tech-support form. Of course you will want to include the details of your purchase along with the request.
NOTE:
There is also an unreleased burning patch that can be applied once the full version of PS4 has been properly installed. I would suggest trying this only if you are still experiencing the "color" problems you mentioned in your other posting. Can't say for sure if it will help but the link is:
ftp://UL915HH6:OIQ41NEF@Private.ulead.c ... _Patch.exe
Hope that helps

-Mike