I have a 2008 HP Compaq CQ laptop that was supplied with Win Vista. The hard drive is worn out, I have bought a Seagate FireCuda 1TB hybrid drive. Due to Vista being both a defective & obsolete OS, I want to move to Linux but at the same time will need to keep a version of windows (probably loaded into VirtualBox) in order to run my legacy database WordPerfect (Borland) Paradox.
My research to date suggests that Ubuntu is perhaps the better starting point in this new adventure. I am not an IT wizzkid but at the same time can cope with some simple programming.
Some experienced advice would be welcome.

My recommendation would be to download the Ubuntu ISO image, write it to a USB or DVD (maybe CD) and install it on your laptop. Install VirtualBox. Purchase an OEM installation disk for Windows 7 or 10 and install it on a VM created under VB.

There is no 'programming' necessary to install Ubuntu or any other Linux OS, just the ability to read and follow simple instructions. There should be numerous sites with instructions on dual booting Ubuntu with vista or other windows systems such as the one below which is at the UBuntu site. You might want to compare your hardware to the minimum requirements for the most recent Ubuntu as a computer that old will probably not run a current Ubuntu.

https://help.ubuntu.com/community/WindowsDualBoot

https://askubuntu.com/questions/1030...m-requirements

You might be better off with a lighter version if you want Ubuntu such as Lubuntu or Xubuntu. AntiX will probably work or you can do an online search for 'LInux on older hardware'.

Your laptop is quite old so it may not have enough horsepower to run Windows via Virtualbox. It would have to run the Linux operating system plus Virtualbox and within that run Windows. If it is working satisfactorily at the moment you might be better to add a Linux Distribution as a dual boot. Personally I prefer Linux Mint 19.2 to Ubuntu but you can try them via a Live CD before making a decision.

Agree with donreid - Mint xfce4 is probably far lighter on resources than Ubuntu. Drop-dead simple install: click next, answer question, click next, etc.

Thank you for the observations, I'll check out Mint. (Ubuntu 18 ISO - 1.9GB - is downloading onto the PC as I type this but I don't need to mount it on the USB key)
I had considered a dual boot with a clean Vista install but I am not sure that I really need Vista as Skype & Dropbox no longer function & Firefox can no longer be upgraded. Support for Win 7 ends next year. This is why I want to migrate to linux.
I currently run my database on Win XP in VirtualBox mounted on Vista with a similar setup on a Mac with OS 10.10.
I will need a network connection between XP in VirtualBox and the linux OS (whichever it is).