This is a fix that will last for a long, long time.
Buy some graphite powder and some oil at an auto or hardware store. They come in different packages. For oil, the best is the pen-type as they are easy to handle and only give a small amount at a time. Just about any oil in a pen format will work fine. The graphite powder comes in small plastic tubes. But make sure you get graphite powder, not graphite oil, its too thin for this job! So you need graphite powder in a small tube and oil in a round "pen" that can be squeezed out and placed just where you need it. Also, when the oil is used up in the "pen" you can open it and add your own oil.
First, clean the fan blades off real well. If you have a heatsink with the fan then clean the heatsink off as well. You can even use a bit of your oil and some q-tips for cleaning if needed. Then, take the small circle, it usually has a name on it, but its in the middle of the fan. Peel one edge up carefully and put a very small amount of oil in where you lifted the label up. Now add some graphite powder in the same place where you put the oil, add as much or a bit more of the graphite powder than the oil. Clean off excess oil and graphite and push the label back where it was. You may need a very small amount of duct tape to hold the label in position and to prevent leakage. This is important if the fan is going to "sit up" as opposed to lying flat.
Now put the fan back where you want it and when it starts spinning it may be noisy for a few seconds until the graphite\oil works its way in. Then it will stop and it will stay stopped for many years and you may very well not need to buy a new fan after all!
I experimented a lot with this and this is the very best way to quiet all those fans and have them work well. I have always been a big fan of those removable ide hard drive trays that you can buy. But the fans are the pits, they get noisy real fast. So i had to find a way to fix them as they are very expensive and hard to replace. Now i dont have to. Combo of oil and graphite is the very best, by far. One caution, graphite stains worse than
oil, so be careful! Im talking about staining your clothes and hands.
You can use this system with all cpu fans, video card fans, system fans, and even fans inside power supplies. But one word of caution, its easy to open a power supply and take out the fan, but do be careful as there are voltages there can can hurt you badly. If you dont know what you are doing then wear rubber gloves to get the fan out and to put the fan back in after the
Trust me, this will work. If the fan spins my method will work for years and I have even fixed fans that were stuck and wouldnt spin! This is better done with the fan on the table but in those cases where you cant or dont want
to take the fan out of the system, thats where the "pen" with the needle comes in again, but i still find a way to get some graphite in as well, graphite is what makes the oil last a long time! And graphite is also an oil, but you need both together for maximum effectiveness. Oil by itself will only last a few weeks or so and then evaporate, and the fan will get noisy again. Its the graphite powder that does the long term job. The oil really only helps to spread the graphite powder around really well so the graphite can do the job!
Hope you do as well as i have with this info!