Dump Spyware Doctor and install Spybot Search & Destroy 1.6
there will be no conflict with yahoo messenger.

If you have adware, spyware or malware resident on your computer, it can be very frustrating. It can cause your computer to run slowly, to crash, freeze up, and may even bombard you with annoying popups whether you are using your internet browser or not.All computers are susceptible to spyware and therefore everyone who is browsing the internet should have a good spyware software to protect their computer and their personal information. That's right! These programs can even steal your personal information!

I would recommend you download MalwareBytes. It's an excellent free spyware utility that finds things that others dont.

www.malwarebytes.org

please remember to rate my answer if it has helped.

thanks

trev

2 possible problems, 1 might be YM has a virus and spy Dr. is protecting it or you can try downloading a safer internet program like firefox