note: Most of the info counts for all win9x. I advice to replace win9x with Linux, it's rock stable, fast and free.
Update windows completely, it's a good idea to safe the updates on your hard drive as MS will stop online support for windows 98.
If you have the English version, you can update Win98se with the unofficial service pack. It includes all official win98se updates and extra's.
Axcel 216 is the best site to find information about tweaking windows, good tweaks are listed there. There is a zip file available for download which contains all the text from the site in textfiles, regfiles,... very handy to find a tweak without need of internet.
98Lite
98 lite can be bought here
It gives us the ability to remove all bloat from windows, keeping it's core only. That makes win98 faster, more stable and offcourse smaller.
With 98 lite you can choose to do a shellswap , I'll explain 2 of the options.
98Lite micro, for the ultimate speed you can pick the 98Lite micro option. This put's the win95 explorer.exe, shell32.dll and Comdlg32.dll into your win98 which speeds things up. It removes some parts of windows like IE (quicklaunch is gone).
The downside is that IE, Outlook Express, msn and any newer office then 97 won't work on it.There are enough alternatives to the MS programs though, I recommend : using Opera or Mozilla instead of IE, Foxmail instead of OE , Trillian or Miranda instead of MSN and Openoffice instead of MS Office. These programs can be found in my "freeware" section.
The MS programs aren't a real loss but the list of other programs that won't work with the win95 dll's keeps groing, there are mostly good alternatives but I even ran into problems with Command and Conquer Generals. It needs the win98 shell32.dll. So I had to open game.dat with The Gun and replace shell32.dll with shell32.w98 to make it work (shell32.w98 is put in the system folder by 98lite).
There is a speed increase but the bad compatability might just not be worth it. Your decision.
Running the 98Lite Chubby shell is easier . It has maximum compatiblity, runs pretty fast, has a quicklaunch and removes bloat like IE. I use this option, wich is the fastest using the 98 shell.
There is a guide to strip win98 more down, called :"SPEEDOS GUIDE". Google for it. A part of it is about 98lite but there's still useful info in it for people who don't have it.
Aston [all windows]
The win9x and win2000 shells look awfull and the costumization options are not satisfying. If you use the 98 lite micro shell you don't even have a quicklaunch, nor a show desktop shortcut.
The Aston shell comes in handy here, it's faster , uses less ram , looks beautifull , is rockstable and gives you a quicklaunch,show desktop shortcut and much more!
Download Aston and install. If it's installed it will ask you to go to the Aston shell. Now you can go to Aston BUT to avoid having problems you should get Litespawn first. Extract the zip-file to your harddisk (e.g. C:\shell\Litespawn). Run LiteSpawn.exe, answer yes to the question if it should be new default shell. Don't reboot yet. Go to the LiteSpawn folder on your hard drive. Open Litespawn.cfg, go to [Alternate_Shells] and change :
altshell_name_1 = "Aston"
altshell_path_1 = "c:\shell\aston\aston.exe" The path where your aston.exe is.
In Litespawn.cfg you can change the defaults in "Default User Preferences", choose default shell, start_delay, etc.
Then restart.At startup choose the Aston shell.
The people who need some more help, you should ask on the Aston forum.
If you make a good theme for Aston and manage to get a good rating at Deviant ART, you'll get a Aston registry key for free. Just some hours of photoshopping and you got that nice theme ;).
HyperOS [all windows]
HyperOS, run up to ten OS's on 1 PC.
All it's options can be read at the site , but I'll give you the main ones :
1. You can run Win98 in hyperdrive if you got 256mb ram or more. It uses a part of your ram as hd space, before win98 is started it gets copied to the ram and then loaded from the ram instead from the slow hd. This gives some big performance increases in office,... . Be sure to keep enough ram available for windows for games tho. 768mb of ram is recommended so you use 100mb for hyperdrive win98 and the rest for usual ram usage.
2. You can manage multiple OS's (up to ten) at one hd, you can hotswap between win98se installations (takes 2 secs) , ....
3. It has a very nice backup feature , which is as well the fastest of the world (so they claim)