Nola,
The EXACT error message would be helpful.
Clicking on the links below should help you get the Yahoo Companion correctly uninstalled. :
How to Uninstall or Turn off the Yahoo! Companion Browser Toolbar
http://support.microsoft.com/?kbid=303047
In addition, have you try running the free spyware removal tools below? They might help you find some "junk" that's causing the issue. Click on the links below, download the installer file to you desktop, install the program, update the program from within it's user interface, then run the program. Delete all spyware that it finds. BE AWARE, some "freeware" programs may cease to function if they are dependent on the spyware to operate. Still, it's better to find new freeware than to deal with the spyware:
Ad-Aware 6 Spyware Removal Tool
?Spybot Search & Destroy? Spyware Removal Tool
Hope this helps.
Grif
For the past 2-3 days, whenever I try to open Internet Explorer I get an Error Message: COMP5_3_11_0.DLL. This had to do with Yahoo Companion Toolbar on my Internet Explorer (version 5.5). I have to un-install and re-install Yahoo Companion Toolbar before I can use IE. I am using Windows ME.
Any suggestion as to what is causing this problem?
Thanking you in advance, I am
Nola

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic