Hi I am facing a problem with my current motherboard - Intel 915GAVL, the connectors at the edge of the board (LAN, USB, Serial, VGA, mouse, keyboard etc) are getting corroded/rusted. The board is about a year and a half old.  I intend to upgrade to a newer board soon.. but I was wondering .. is there anything I can do to prevent such corrosion.. ??

You need to stop dipping you computer in the pool, sorry I just couldn't help myself. Is you climate wet or damp? Even my connectors get dusty but nothing a soft nylon paint brush won't clean, but don't ever use a brush made from a horse hair brush. I even have anti-static spray that I use to clean my computer with, you can get it at any Radio Shack.

Unfortunately humidty is very high here ranges normally around 40-50% and gets worse during rains.  
 
Is there anykind of polish or coating that can be given to the connectors to prevent them from falling apart.

 
It depends on how bad the corroded they are, but any metal polish will do. You must make damn certain that you clean and dry everything up! Sounds like you need a dehumidifire in your computer room, yea I know my spelling is bad.

Just a possible way to work around this issue...
 
Do you have ALOT of fans in your computer on to keep things cooler?  Maybe if you unplug some of the fans so that it's warmer, but not terribly hot this would help.  Might help keep the moisture in the air from reacting with your computer.  Kind of like the way defrost in your car works.  Just a crazy idea at 4am.

Thanks for that Cyberjock, but cant afford to switch off the fans.. the things as its runs very hot (approx 60 deg C). I have heard that nail polish varnish is good if you apply it before the damage is done.

I believe you are screwed. You can't paint the connectors with nail polish or varnish because they will stop working.

Not yet.. I was told this was one option to prevent corrossion...  But then just a query.. see there are no issues with the pins.. they are generally gold coated or something like that so corrosion does not affect them. Its the surrounding (which holds the pins in place) thats plain vanila and get corroded

WD-40, it's a water displacer not a lubricant, non-conductive
and desinged to keep things from corroding.
 
WD-40 stands for "Water Displacement, 40th attempt",

dielectric grease found in all auto shops or electic motor cleaner none corrosive kind

That would probably work, messy though.

Edit: I should have thought of that. I just got done packing my TL1000 wiring harness connectors.

If the connectors are oxidizing, then other parts on the mobo probably are as well, So I don't know whether it will extend the useful life of the mobo.

If the pins are not corroded, I do not see a problem.  It is the pins that do the connecting.   If the pin mounts are corroded, then use a dremel with polishing cloth at a low speed to clean the corrosion (this would have to be extreme in order to matter much) and almost any good car wax will provide a thin protective layer that is not noticable.

I do not recommend using any products that are not designed specifically for electronics use.
 
I am not quite clear about where the corrosion is.  Could you post a picture of the corroded areas?
 
If I had a circuit board that was experiencing corrosion, I'd first check for any corrosive chemicals stored nearby.  Corrosive vapors can have a dramatic effect on unprotected metals.  Humidity could be a factor, especially if it's combined with bad air pollution.
 
One possible solution would be to conformally coat the circuit board.  This is a rather drastic step, but a properly-applied conformal coating will virtually seal the circuitboard and its components away from moisture.  This is effectively a plastic coating; be sure to carefully mask any connectors (IDE, SATA, USB & IEEE 1394 headers, fan connectors, etc) before spraying.  The conformal spray will also act like a glue, so you might also want to remove the RAM DIMMs and CPU (being sure to mask their sockets carefully).  Mask the top of the connectors with masking tape.  Be sure that none of the coating gets into the body of the connector where the mating part fits, or it might get too tight.
 
To conformally coat the board: disconnect the board, clean it thoroughly with industrial isopropyl alcohol (not rubbing alcohol!), let it dry, mask all connectors as described above, and then spray the board with conformal coating spray.
 
Conformal spray is available from electronics distributors such as Mouser, who carries a series of Fine-L-Kote conformal sprays.
 
Let's see some pics before you try something like conformal coating, though.  Use macro so you can get right close and personal, and please make sure that they are in focus, and not washed-out.
 
Regards,
 
Altazi