Set up the latest Tiny Core Linux v11 on a > 10 year old netbook yesterday, the only household SSE2 capable hardware. Using OpenBox window manager, iptables firewall, Dillo and the latest SeaMonkey v2.53.3. The operating system for the job gets booted, even if not an all-time favourite. Here it's GNU/Linux (Devuan Jessie and Ascii, Debian Wheezy, Tiny Core). Two Windows XP installs primarily used offline, one for graphic art/print projects and the other for Windows gaming and last year an official income tax return.
Of the two Windows 98 SE installs, the primary is used almost daily for news and forums, some YouTube, retro gaming and computer learning. The other is a backup in storage. Rediscovered some 500-700 MHz processors in the basement, should be able to run Windows 98 SE on bare metal for a long time. Hope to free a 10 GB hard drive later this year for a third Windows 98 SE build, a 'slower' system primarily for DOS and early Windows gaming. Found a Pentium 4 processor but no motherboard, it may eventually become a high performance Windows 98 SE machine.
MemTest v7.0 from HCI Design (2019, free for personal use, MemTest.zip, 17 KB) allows testing system memory for faulty RAM modules. It runs from within Windows, as instructed close as many open applications as possible before testing. May be useful for quick convenient testing, otherwise seek memory test software that runs outside the OS (boot floppy or CD, boot loader). Personally an old GNU/Linux live-CD is used to MemTest questionable RAM.
https://hcidesign.com/memtest/
Since my Windows 98 C:\WINDOWS footprint is probably larger than the new and shiny Tiny Core install, i'm interested again in a more minimal install, which won't get trialed until fresh hardware becomes available. My experience is these 'lite' tools are best used after a fresh Windows 98 install, before too many customizations. As indicated earlier, Kan's Minimum Windows 9X Install Project (minwin9x.zip) was used previously with good success.
https://msfn.org/board/topic/177106-running-vanilla-windows-98-in-2020/page/25/?tab=comments#comment-1179823
May look at 'winimize', although the current website needs JavaScript and does not work in RetroZilla. A direct download is available below, unsure if it's the latest version to trial. Maybe forum member @jaclaz can clarify.
http://web.archive.org/web/20060712175942/http://www.winimize.com/min98.zip
Another option is 98lite v4.5 Preview Edition (98lite45.exe, 319 KB) and IEradicator (IEradicator2001.zip, 200 KB), both free for personal use, license acceptance required. Promoted as a 'custom installer for Microsoft Windows 9x'. Can be used to remove Windows 98 web integration, Internet Explorer and convert default features to removable options.
https://www.litepc.com/preview.html
https://www.litepc.com/ieradicator.html