How to browse the web on very old computers

This guide is made for people who want to browse the internet on older operating systems despite most web browsers don't support any of the following OSes below. For Windows XP or Vista see How to browse the web on old computers

Using a proxy
You can use a HTTP 1.x proxy like WebOne to get rid of cipher/security errors on old browsers.

Browser-in-browser services
This may be cheating but you can also use Browservice or WRP (Web Rendering Proxy) to sort-of give new life to old browsers like IE 1.5.

X11 Forwarding
This one may also be cheating but, if you happen to have a machine running *NIX with SSH enabled, you can forward a browser like Firefox or Chrome to your computer

Using ad-blockers
Blocking advertisements is generally a good idea for old computers as it can reduce less CPU usage (by not rendering those advertisements) and such.

For Firefox 45 or later, you can use uBlock Origin Legacy

For Firefox 2, you can use Adblock 0.5 or Adblock Plus 1.0.2 (both are on the Firefox95 page in a zip) with an up to date list compatible with either of those extensions

For Opera, you can use Fanboy's Adblock List for Opera

If you're using a system that sucks with browsers other than IE, you can use pi-hole so you don't need any installation on the guests. Only changing the DNS is required to point to the pi-hole instance and block all the yucky ads that have 8 megs of javascript to be loaded.

QTWeb
Browser made with QT 4.8 and QTWebKit and is lightweight.

Homepage

This browser was used on Windows 2000 CollabVM.

Seamonkey
Continuation of the Mozilla Application Suite.

Seamonkey has an IRC client, mail client (which is based from Mozilla Thunderbird) and a WYSIWYG HTML Editor.

If your CPU supports SSE then use Seamonkey version 2.9.1, if it doesn't support SSE then use Seamonkey version 2.8.

Pale Moon 26.5 & K-Meleon 74
Two excellent ports of Pale Moon and K-Meleon to Windows 2000 by roytam1.

Download it here.

Windows 98SE-ME
98FE isn't included as it's an memleaking piece of shit and it's not advised to be used, but it may work with these browsers below.

Firefox
Last version to run under native 9x with no modifications is 2.0.0.22 (nightly version).

With KernelEx you can run up to 52.9 with modifications/updates,

However if you don't want to bother with that or because your CPU isn't advanced enough, 3.6.28 works just fine.

Opera 9.64
Final version of Opera 9 and the last one to run under 98. Requires MSIMG32.DLL from Windows ME (for 98 users).

Windows 95-NT 4
First Windows versions to include NewShell.

RetroZilla
Best browser for Windows 95 and NT 4 out there,

Has TLS 1.2 support (roytam1 fork) and various security fixes.

Homepage (requires a browser capable of modern ciphers)

Opera 10.63
Also best in terms of HTML5 support,

But a bit tricky to run...

Note that you have to find the classic variant of the installer to actually install Opera 10.63.

And if you want TLS 1.2, get DOSFreak1's modified Opera 10.70 build 3488.

Here is how you fix it (works only on Windows 95).

K-Meleon 1.5.4
Think of K-Meleon as like, the liter version of Firefox/Mozilla.

Uses the Gecko engine (older versions, newer uses Goanna)

Download

Windows NT 3.51
Last Windows version to include the Windows 3.x style.

Seamonkey95/Firefox95
Seamonkey patched to run on NT 3.51 and 95,

Also has a Firefox version with the same patches.

(Requires some updates to NT 3.51, including post-SP5 hotfixes.)

Download is here.

Opera
5.12 runs fine with some minor issues (fixed when NewShell is installed) while 6.xx crashes when rendering web pages or hovering over UI elements and

7.00 has major graphical glitches (newer releases simply don't start), although it's recommended to go with 3.x 32-Bit releases instead.

Internet Explorer
Only 16-Bit versions of IE will run under NT 3.51, this is an artificial limit from Micro$hit themselves, up to 5.5 runs as well as under WfW 3.11

(but with slight performance increase) and same limitations apply as if you were running the browser under WfW 3.11 itself.

Netscape Navigator
Versions up to 4.0 run fine on NT 3.51, not recommended as there are clearly better options to work with, however if your machine is too slow to handle Firefox on NT 3.51, then this is an good alternative.

Windows For Workgroups 3.11
Even though almost no one will use Windows 3.11 we will still list browsers available for the operating system.

Netscape Navigator 4.08
Best browser available for Windows 3.11, a bit slow but gets the job done.

Opera 3.62
Lightweight, but requires a license number,

Also the latest browser made for Windows 3.11.

Internet Explorer 5 16-bit
ActiveX support has been stripped from this version, JavaScript support is crippled compared to the 32-bit version of IE5.

3.0 is recommended since 5.0 can sometimes hang your 486 and make windows glitch out and corrupt your .GRP files.

Arachne
Works fine if you want images.

(Also doubles as a dialer and an email client.)

Dillo
This is also graphical like Arachne but probably has more support for HTML+CSS

Links
Text-only web browser, works pretty well.

MicroWeb
Web browser meant for 8088 class machines.

Currently, it has basic HTML support and only supports HTTP with no encryption.

Github page