Help! My Mouse Is Being Ridiculous!?

My mouse will not drag and highlight text...It's getting annoying and I have no idea what the problem could be. I already reset the computer, turned it off last night and turned it back on and the problem was still there. I can't drag and drop things with my mouse at all, it's like I'll click on it and it'll highly briefly before it gets screwy with me! I'm tired of it!