Well although I have a reletively new PC (just 14 months old), the keyboard has accumulated what seems to be like dust (by virtue of the PC being situated beside a window), now the problem is that I find that a few keys have become "hard" , is there an easy way to clean out or "soften up" the keys?

You can use canned air to blast out the debris, remove each stuck key and manually clean the area, or (if your adventurous) put it in the dishwasher (just make sure you let it dry for a day). I've only heard of one person actually puttin it in the dishwasher, but supposedly it did the job. No guarantees though.

IMO, if canned air doesn't work, I'd just pop off the keys and just rubbing alchohol to clean the junk off.

Doesn't the dishwasher thing seem too risky? Anyways, a good vacuuming did the job, but i want to know how to get rid of "sticky" keys, how do i lubricate them?

As I said, I've only heard of the dishwasher idea once. Since keyboards are (relatively) cheap, when you upgrade your system you might as well try it and see what happens.

You can try using rubbing alchohol to get rid of the stickiness, if it's something like spilled coffee or Coke. If you haven't spilled anything like that and the key is still sticking, then your next action would probably be to lubricate the actual key springs. Look for a special electronics cleaner just to make sure you don't damage the keyboard; it works similar to WD-40.

is it necessary to to disassemble the keyboard to do it, or do you have any work-arounds? Otherwise I'll have no option but to do it (which I'd like to avoid if i can). Anyway, thanks a lot crystal.

The easiest way is to just pop off the individual keys using a small screwdriver or similar. Just pop them off one at a time so you don't get confused when putting them back (unless you have a good memory )