The cache is under Tools>Options in FireFox or Edit>Preferences in Netscape or in IE Tools>Internet Options>, then under Temporary Internet Files, click delete files. Like I said I don't know that this will help. It's just a suggestion.
There's also a program called
CCleaner that'll clear them for you(it's free). If you do install it, watch during the install process it asks if you want to install the Yahoo Toolbar. Be sure to untick it if you don't want it installed on your computer.