Henry is right but if you have plenty of spare time and are probably going to replace it anyway then you could try this. Most are made with a hole in the in one of the corners for the side or bottom that goes in between the panes. They inject the argon gas and then plug the hole. Look all around on the inside for a hole between the panes and do the same on the outside. Carefully drill it out with a small bit. Then vacuum it out(vacuum pump or cleaner), pump argon back in or put some dessicant in there (probably have some that got shipped with your computer) or some other type of dryer, and then reseal with a rubber plug or caulk. You may need an escape hole to get the air out if you pump argon.
I haven't tried this but plan to next chance I get. I may also get flamed by the others for this too. It may or may not work and a lot depends upon how bad the seal is but if you can get a bunch of some type of dessicant/dryer in there, that may stop some or all of the moisture that does come in through the broken seal. Also do this on the driest less humid day possible if you don't use argon. They also make some spray dryer used around car ignitions and a little sprayed in there may work if it doesn't leave a residue on the inside of the glass. Argon can be had at welding supply houses and maybe a welder that uses it on his wire feed welder may give you a squirt.