chronic grinding/whirring noise?

Turn off the laptop, turn it over, make sure that nothing is blocking the fan, and that nothing is touching the fan. Also, clean out any dust (Either by blowing in it or getting a can of pressurized air), should help.

If the dust accumulates enough in there, or your fan gets obstructed, your laptop would automatically shut down, and it sounds like it's getting to that point. I would open up the fan panel and check to see what's up in there...you probably have a fair sized hairball messing things up.

or the bearings in the fan are shot, and the only fix is a new fan...

I had the heat sink fan go bad on a laptop I owned in the past.... I was overseas at the time and unable to get spare parts so I kept running it. To make the story short I ended up terminally overheating a $2000 gaming laptop... not a good thing to do, so I'd reccomend that you not use it if you can avoid it, until the problem can be addressed.

Could be the hard drive. Try to make a recording of the sound. :P

you're playing an mmo, where do you think the grinding is coming from -.-

Here is what you can do. Next time the noise starts, take a paper clip and unbend it a bit, then slowly insert it into the vet for the fan, if after you stop the fan the noise stops then you will need a new fan. If it is making noise like that then cleaning it out with a blast of air is only going to be a temporary fix.
Call Dell support and give them the service tag information and then ask them house much a replacement fan is going to be. Those fas can go for anywhere form like 20 to 150 bucks depending on the type. Now actually replacing said fan, i would leave up to he pros. Depending on the model you might just have to remove the keyboard and some screws, or you might have to take the WHOLE top off. I would get the fan and take it to a certified repair place. It will be cheaper than a whole new laptop for sure.


/10+ years as a computer repair technician ftw

Ha.

Let's keep it on topic, shall we?