my home networking just uses normal ethernet, so getting an internet connection is not very hard. however, tls 1.2 with something better than aes-cbc is nowadays required for connecting even to wikipedia, so the built-in internet explorer 6 is not very useful in modern day internet (google still works tho!)
I first tried to see if I could bootstrap tls 1.2 capable browser using only windows xp. this is possible on os x 10.4 – macintosh garden allows non-https requests if you are on an old mac, and they host the most up to date browser for the system. you can even get all the way to latest openssl staying 100% on os x 10.4
as best as I can tell, it is not possible on windows. everything able to do tls 1.2 is behind tls 1.2 (and in several cases, behind github, which is completely unusable even on the tls 1.2 enabled browsers that do run on these old systems). so I just copied firefox 52.9esr (last version that supports windows xp) installer over on an USB stick, and ran that
except it turns out, that requires SSE2 (second picture). and my laptop has athlon xp-m, which only does up to the original SSE. and the latest version of firefox that did not requires SSE2 was 3.6, far too old to have tls 1.2. I then set out to look for a browser without an SSE2 requirement
my first lead was chrome, which added SSE2 requirement in version 35, and tls 1.2 support in 29 (with chapoly in 33). I quickly determined the version I wanted was 34.0.1847.137 so now it was only the matter of finding that. that turned out to be harder than expected
google does not host old builds due to security reasons (fair enough), so if you need an old build for development reasons you are supposed to find the matching chromium CI run and get that. however, using the linked tool for finding the base position (which is deprecated, because of course it is) does not find a base position for 34.0.1847.137. after some time a friend came to the conclusion that chromium no longer hosts CI builds that old
at this point another friend suggested k-meleon, the on-off updated windows-native gecko (now goanna, pale moon's engine, after mozilla killed off support for gecko in third party applications) browser. this did in fact work, as you can see in the latter two images, though goanna is clearly showing the lack of developers compared to gecko and it is not able to for example view individual toots' pages on mastodon
(said friend also suggested the mypal web browser, which is based on pale moon and targeted specifically for windows xp. it however died on an illegal instruction, which suggests to me that it too requires SSE2)