Abiword ceased being supported for Windows 13 years ago. If you want to try getting it to install on a current version of Windows, download and run this file:
https://www.abisource.com/downloads/abiword/2.8.6/Windows/abiword-setup-2.8.6.exe
However, as that version was designed to be used with Windows 7 and 8, there can be no guarantee that it will install and run correctly under either Windows 10 or 11.
The majority of AB users seem to use one of the following:
(a) The full version Microsoft 365 (which requires a paid subscription) ; or
(b) Microsoft Office 2021 or earlier (which requires a one-off payment) ; or
(c) the free, online version of Microsoft 365 (which costs nothing but means that you have to do everything via the web)
https://www.microsoft.com/en-gb/microsoft-365/free-office-online-for-the-web ; or
(d) LibreOffice (which is a totally free office suite, based upon OpenOffice, which you can install on your computer)
https://www.libreoffice.org/download/download-libreoffice/
[If you use that link, opt for version 7.4.7]
Another excellent alternative to AbiWord though is TextMaker, which forms part of SoftMaker FreeOffice:
https://www.freeoffice.com/en/
(I've got
both LibreOffice and SoftMaker FreeOffice on my computer).