I'm using MSIE 6.0 and Flash Player 7 in Windows 98, and alot of times
I'm working in Yahoo Mail on the web, and having problems with the
browser crashing.

Microsoft sent back a message after one of these crashes tonight,
indicating the problem was with the Flash player. I updated the
Shockwave player, but could not find anything to fix the Flash player.
I assume Yahoo uses alot of Flash in the ads, the Yahoo Mail
interface, etc. Where do I go from here?

The problem, by the way, does not appear in Hotmail, Google, or other

Well sounds to me like M$ is passing the buck for their own unstable software,
but there is not much you can do about that. One thing you might try is to zap
any bad ads with a HOSTS file. For example if you view source on the page you
are having trouble with and see that the .swf's are coming from
http://us.i1.yimg.com/, you put a line in your HOSTS file 127.0.0.1
us.i1.yimg.com and they will never bother you again.

For more information on how this works and how to use it:
http://www.mvps.org/winhelp2002/hosts.htm
I wouldn't leave home without it!