ok so its a HD 2400PRO card thats definately out of warranty
you have the understanding you need, what happenend was the dust got under the fan blades hub and into the bearings and it worked like a wick to suck the lube out of the bearings.
you cant remove the blade without breaking it and you cant get anywhere near the blade shaft or bearings to get any lube in there so you must flood it with grafite spray or light weight oil (sewing machine or 3 in 1 oil) wd-40 in a pinch.
your gonna work your azz off and its still going to fail on you sooner rather then later and your video card will be running hotter then it should until it happens. small tiny fans like that with poorly lubricated fans can lose as much as 10% of the cfms they put out.
my solutions are relace the fan with a generic replacement after you measure to find the size you need (it goes by the total circumfrence)
if its a 40mm fan (1.5 inches) then you probably wont be able to replace it
1.77 inches = 45mm -
http://www.newegg.com/Product/Produc...82E16835119081
1.99 inches = 50mm -
http://www.newegg.com/Product/Produc...82E16835119083
the trouble is your card is so old its not shown as compatable for the majority of vga coolers that look like yours.
BUT: you could also just replace the whole card with a ATI 5000 series card and 512mb of onboard ram for around $50 which is twice the card you have now.
if it were me i would make one of those replacement fans fit or buy a new card but i wouldnt spend $30+ on a good VGA cooler just to find one that fits your card
go to the hardware forum and ask if anyone has an old hd2400 you can get the fanless heatsink from so you dont need a fan anymore or you can try those computer help forums that buy, sell, or trade computer stuff.
hope that helps