Don't install Windows XP in your computer. Its extended support was discontinued in 2014. It would be very much prone to malware as soon as you connect to internet. AFAIK, major browsers have stopped supporting it too.
Either use a Virtual Machine to run Windows XP inside Ubuntu, or use Wine to emulate the software.
Also, many popular Windows software have equivalent free and open source software in Ubuntu, so we may be able to recommend you an equivalent software if you tell what you need.
Less RAM issue
2 GB RAM is not enough for Ubuntu 20.10.
I suggest you to use Xubuntu or Lubuntu 20.04 instead (or Kubuntu, without any fancy effects. The RAM usage of Kubuntu is very similar to Xubuntu). They need relatively less resource to run. Also, the 20.04 version is a long term support release, so you can stick to the same operating system for a long time.
In case even Xubuntu or Lubuntu seem to be slow, you can use other distros tailored for older computers. Some examples of such distros are LXLE, Puppy Linux, anTiX or Bodhi.
Note that they are not supported on this website. But being Debian based, the user experience would be very similar to Ubuntu.
Alternatively, if you don't need to regularly connect the computer to internet, you can use an older version of Ubuntu (e.g. Xubuntu 14.04). That would be still a lot safer than Windows XP (even such an older version of Ubuntu won't be affected by a USB drive affected with virus).
With such a lighter OS, you would have enough free RAM to run a virtual machine (even 200 MB RAM is enough for XP), or emulate the software in Wine.
lenovo thinkpad sl510 (c2d-t6570, 2gb ram, i915)
– guiverc May 06 '21 at 22:39