I have a Toshiba Satellite laptop and I booted it up for the first time in about three weeks. This message popped up saying that the cooling system was having issues and that I should shut it off and call someone. I have had this laptop for 1 year, so my warranty is gone, plus I sent it in in March of last year for a hard drive replacement. Only THREE months after I bought it. I just bought a gaming desktop, so this is something like my travel computer. In the span of three weeks, I have kept it in its case. The only thing I can think of that would've gone wrong is this one time I was playing Left 4 Dead, either one or two, and my pc was getting pretty hot, but not that bad, and it just shut off (noting that it was plugged in). I turned it back on and it was fine and I didn't get any warning messages or anything. I am definitely not going to send this thing in for some expensive repair, and I checked the Health Monitor and fan speeds/cpu temps were perfectly fine. Should I be concerned about this, or just ignore it?
You could remove the battery and power cord, and then remove the panel covering the heatsink and fan to see if there is dust or other "stuff" impeding the fan's running.
-- If it's dusty, you could use canned air to blow it out of the fan.
-- If it is not dusty, spin the fan to see if it spins freely.
-- If it spins freely, reconnect the battery and turn the system on, so you can see if the fan begins to spin.
-- If the fan did not spin freely, or does not start spinning when you turned the system on, you have a dead fan. Contact the manufacturer (or go on eBay) for a replacement.