I broke down and bought a carpet rake and it's awesome. I raked and then vacuumed my 10 year old carpet and it looked great. It's not a permanent fix and needs to be done about once a week but it works. If you do go with the rake, use it before cleaning the carpet so the pile lifts and the cleaner can get the ground in dirt out.

How about using a wire dog brush? They cost about $10.

I would not use a wire brush, because it could tear up and separate the fibers.

The more expensive thing to do is to rent a Pile lifter machine. It is like a very aggressive vacuum cleaner, that lifts and separates the nap.

Get down and look at the carpet. Does the high traffic area carpet fibers look like they have separated. If they have and have mashed down flat, that area will not look like new again. The carpet fibers may be damaged for good.

You must make sure that you are using a vacuum cleaner with a rotating brushroll-upright or canister with a power nozzle regularly. Find out which direction the nap of the carpeting lays flat in the room. Use your hand to sweep in the four directions. After you find out which direction it lays flat and which direction it stands up, you want to vacuum so that the final back stroke pulls the nap up. You have to vacuum like this all of the time, especially in high traffic areas.

Make sure that the room is deep cleaned regularly and that there is no residue left after the cleaning. Detergent residue will stick the fibers together.

The top third of the fibers look like they have come untwisted or separated, but the bottom two thirds looks about normal. So is there no hope? It doesn't have to look like new as long as it's able to be vacuumed. As it is the vacuum isn't picking anything up even on the bare floor setting. I have a carpet cleaner, but I'm wondering if a more powerful cleaner--like one of those rental Rug Doctors--would do a better job.

We've had nothing but problems with the carpet since we moved in. Apparently our $80 vacuum was so powerful that it was making the carpet fibers disintegrate or something because we had a few bad clogs of carpet fibers (and this isn't new carpet where that would be expected.)

I would love nothing more than to get rid of the carpet. We live in an old building and there are beautiful hardwoods under there. The carpet was put in at some point during the previous tenant's occupancy, and I'm pretty sure it was the cheapest polyester carpet out there.

Just a note: I'm pretty sure the problem is not with our vacuum. It's less than a year old and has worked wonderfully on every other carpet it's been tried on.