Car will not start; screeching noise in fan area under hood

What is your question?

1. Car would not start; it did turn over so not battery. Had it towed to garage. Service man started it; no problem. 2. Car intermittently makes a screeching, like something is rubbing. I opened the hood; it sounds like it is coming from the fan area; the blades are not loose and spin OK; belts are tight, no slack. It starts and stops making noise for no reason; I believe the engine is warm when it makes the noises; I don't recall it making the noise when I turn on the engine. Thanks for any info you can provide.