When you use web mail, it's common for only the titles of incoming to be downloaded to you until you click on the message. With a slow connection (like mine) it can take a very long time for the actual message to be downloaded, after the click, so that you can read it.

Also with web mail (viewed in a browser¹), the message usually does not "persist" on your computer when you leave the email site. If you want to look at it again the next time you check your email, it has to be downloaded again.

When you compose a message to send, it would be setup in RAM, and would send from there. Unless it's a large message, your computer probably wouldn't need to "page it off" to virtual RAM on the hard drive.

Incoming messages, though, don't necessarily go into RAM, but go instead almost directly to "scratch space" on your hard drive. Normally, you read web mail from your "Temporary Internet Files" folder in recent Win versions, and I think it was the same for Win98. Incoming email goes (almost) directly to the Temp Int folder, and then has to be opened from there (transferred in bits and pieces in and out of real RAM) for you to read the message. (Most browser pages do the same.)

If you haven't done a disk cleanup recently, your Temp Space (on the hard drive) may be just too full for incoming messages to be received(?), or at least may require a lot of "paging" to fit them into the available "virtual RAM" on the hard drive.

In WinXP and similar "modern" Win versions, Start|Programs|Accessories|System Tools will get you to "Disk Cleanup" which will offer you the option to "Delete Temporary Internet Files." I think Win98 should have something similar. You can also go to Control Panel|Internet Options which gives you the same utility you get as when you click "Tools" in Internet Explorer. The "Delete" button on the General Tab will look for files that are "candidates for deletion" and you can then choose to delete as many as possible. "Temporary Internet Files" and "Browser History" can almost always be safely deleted. Delete Cookies if you feel safe with remembering how to log back in here.

If you do the "Internet Options" thing in Control Panel, with your browser closed, you should get a fairly complete cleanup. Doing it in Internet Explorer may leave some "residue" since files that are open/in-use when it runs can't be deleted.

While I can't rule out some setting in your Yahoo!® account, in your browser, or in your Win98 that could conceivably cause the problem described, the most common cause that I've seen is just overstuffed Temp space on your computer. Win98, IIRC, can only use 5 or 10%² of the contiguous free space on the system drive, so if you haven't defragged recently, and/or if your drive is fairly stuffed, you may just have gone past the limit for good operation.

¹ Some email programs (like Outlook and/or Outlook Express) will show you a "Local Folders" area in your email setup and if you move messages from the web folders where you view them into a local folder they do actually get saved on your machine. I haven't heard of this option in any browsers, but it's a possibility.

² The 10% limit is a default, and in Win98 it can be changed (again IIRC), but the requirement that the temp space be contiguous may prevent a change from having any real effect, and too large a temp space assignment can crash the OS - especially Win98.

John