I have had the wonderful droid incredible for about seven months now, and since the froyo update it refuses to stay on silent or vibrate. I use the rocker buttons on the side to change the volume, but I find that within a minute or two, as soon as I get a text message, It has managed to take itself off of silent or vibrate and I would really like to know how to fix that. My calc 3 professor got quite annoyed about it, so help would be appreciated 
Thanks.
Thanks.