Can my old netbook be useful again?

I've got an old netbook - Samsung NC20 - that I bought about 5 years ago.

Back then it worked fine for browsing and Word document editing.

I recently had a need to start using it again after a long break. I got a guy to re install Windows XP and some other apps to give it a fresh start.

However, it is now blisteringly slow. Right clicking on an icon takes about 1 minute before the menu is shown.

Browsing in Chrome is almost out of the question. Opening Word takes an age.

It defineitely wasn't this bad all those years ago - are apps now more resource hungry?

Is there any way I can rehabilitate this machine for casual use?

The specs are:
CPU: VIA Nano 1.6GHz, 896MB RAM
Windows XP SP3
HDD: 140GB with 80GB free.
I use Avast to check for virus and I defrag with Auslogic defrag.

Should I reformat and install Ubuntu or something like that? Or can it be used with Windows?

Thanks