My ATT Yahoo mail started to run slower. Typed words appear very slowly?

Sometimes the pages reload slowly, but the one symptom no one has mentioned here is when I type the characters are slow to appear. I have ran several security programs ( Yahoo-McAfie Internet Suite. Windows Defender, Malware Bytes) more I don't remember at this time. Is there a virus or is it a settings problem. And yes I triad a Virus software scan mentioned here,( Beagle Virus was mentioned to be the culpert) ) which told me I had over 1000 erorrs and that they would fix 100 of them for free. The others would cost and there would be no promise that the virus would be remover