As stated it can be replaced. Might be the pits in finding the replacement fan, though.
Let's take a look at an Acer Aspire 5520 series laptop, as an example,http://www.insidemylaptop.com/take-apart-acer-aspire-5520-laptop/
Scroll down until you come to the third photo.
Getting to the Cooling Fan in the Acer Aspire 5050 series Notebook PC's, requires a lot more disassembly, however.
The Acer Aspire 5050-3242 Notebook PC, in the category heading, is part of the Acer Aspire 5050 series of Notebook PC's.
This is the Service Manual for the Acer Aspire 5050 series of Notebook PC's,http://www.tim.id.au/blog/tims-laptop-service-manuals/#toc-acer
Go to the second Aspire heading.
The one that begins with Aspire 1200.
Now go down to the 5th line, and scroll across to > 5050.
Left-click on 5050.
This is a PDF file.
The computer you are using now has Adobe Reader on it, which uses PDF files.
[ Although I would recommend upgrading to Adobe Reader 9, if it isn't on your computer ]
After you click on the file > 5050, you won't see anything happening for up to 30 seconds.
Most of the time the first page pops up within 10 seconds, and it requires additional time to fully download the file.
Suggest you let the file download all the way, before looking through it.
Watch the Download Progress bar.
You can save this file to your computer.
This way you can burn a copy to CD for safekeeping, and easy access anytime you wish.
You can also delete from your computer then, to save Harddrive space.
If you do not know how, and wish to, simply post in a Comment.
For further questions on this please post in a Comment.