Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
If you can hear the garbage disposal running but it seems to be "spinning its wheels" by not grinding, the blades may be broken. It's usually easier and cheaper to just replace the entire unit.
When water stands in the sink, it means the drain is clogged either in the disposal or further down the drain line. This actually isn't a garbage disposal problem, it's a plumbing problem. See our advice on unclogging a drain.