mmmm... guitar is not easy, it requires time and dedication, at first many people drop it cause they dont stick enough to see the results of playing daily but, keep practicing and you'll get better, the problem might be you dont know what to practice or where to find it right?
first thing is tune your guitar, you may buy a tuner at the music store, it might be like $10 USD? or cheaper i dont really know, with this you can tune your guitar and play it right.
A stands for LA, B stands for SI, C ->Do, D->RE, E->MI, F->FA, G->SOL; when you read on the web "Em" or something is a chord, a chord is when you play more than one string at the same time, you can find how to place your fingers to play the chords here:
http://www.all-guitar-chords.com/index.php
if the chord is like this "E" it means its Major, if it's like this "Em" it means it's Minor etc...
next, there's a standar tuning for a guitar is EADGBE, it means, the 6th string or the thickest is tuned E (MI), the 5th is tuned A(LA), etc... you should be able to see this things on your tuner its no big deal.
another common tuning for guitars is drop D, it means you tune your guitar as following DADGBE, so the 6th string is tuned D (RE), this means that once you have your standard tuning you have to "drop" the 6th down so you get a D. this should be easy if you buy a tuner.
and if your guitar is as old as you say and you never play it your strings must be rusty, so you might just go to the nearest store and buy a new package, they're cheap, dont worry.
there's lots of info on the web, you shouldn't have any problem but search for it, and try reading some before you go and play.
an easy nirvana song? Smells...,
search the web on how to read tab's and chords, you'll see it's real fun, but i strongly recommend you find a teacher or a friend to give you some kind of advice or class just to start with the right foot and then if you want, keep on going solo, or drop it if you want, but advice over the web ?? no good, i mean, i'll help if i can, and many people will try, but nothing like the real thing.
