Oblivion is a game I can't complete and i'll tell you why ...

I have easily over 400 hours logged into the xbox version of oblivion ...i have EVERY achievement apart from two . 
 
Guess which ones they are ? 
 

Install it to your hard drive, that should stop the crashing. 

Why do you have to buy it every time?

You haven't completed the main storyline? Really? And yet you logged in 400 hours?

I have only ONE acheivement to get and I've got all of the them. And guess what? It's the 'Duke of Mania' quest. 
 
I don't exactly know why I can't complete it. I think there was some bug in my game that prevented me.  But looking at that '59 of 60 Achievements' taunts me, especially considering that I've put nearly 1500 hours into the damn thing finishing every quest and visiting every single location in the game.

That's weird that it crashes every single time. Try installing it.

I wish that was the reason I couldn't complete Oblivion back when it came out in.. 
Heck even the GOTY edition which I bought (For the PS3 though) I didn't complete. 
Sure I did all the damn side quets and all that (Again) but the main quest was just sooo boring that I couldn't get through it :( 
I would gladly trade with your game crashing for my "boring story" thing though :P 

Well, I would grind out every single ruin, mine and cave. Often repeatedly as I levelled higher.
 
It was silly, really. But I was hooked on the game.

" @Liminality: becuase i loose the desire to play the game after about 2 minutes ....so i sell it...then buy it ...then sell it ...this has been going on for about 3 years :( "

I beat oblivion pretty quickly since everything scales, I think I was a level 8 orc or something stupid like that and I just hit things in the face with a giant hammer. I thought the world was pretty boring.

Buy it once more then don't sell it again. It's a game that you should always have in your collection.
 
Oblivion is awesome beyond belief i personally think. 
 
But i have also experienced the game crashing when i always did that leveling trick by attacking those frozen monks in that shrine in the southwest part of cyrodil. Can't remember what the place is called.
 
Anyways, that Champion of Cyrodil was the only one i need also. All those damn oblivion gates.

I couldn't finish it either, but for other reasons.  Instead of focusing on the main story lines, I went and did a shit load of side quests, and then got completely bored of the game.

If you know you're going to rebuy it, why do you keep selling it? Are you actually that impulsive?

" Buy it once more then don't sell it again. It's a game that you should always have in your collection.  Oblivion is awesome beyond belief i personally think.  "

I hated Oblivion. Beat the Mage Guild sideplot, and that was enough closure to get me to stop. So boring and repetitive, Jesus.

Actually, it sounds like you have a worse problem than being addicted to the game. You sell back games and rebuy them every month? Uhh.... what?

I actually did the same thing as this OP. I owned Oblivion and hated it, but still decided to buy the GOTY edition for $20 just to give the game a "fresh" second go. Needless to say, I never even made it up to the unplayed Shattered Isles content before deciding prematurely to call it quits. I don't think I'll be going back to Oblivion a third time, I've already decided it's one of those rare games that everyone else loves and I hate. The only other game I feel that way about is Bioshock. Generally, I tend to go with the flow as far as enjoying games goes. Oh wow, epic amounts of alliteration there.

That sucks, you should try installing the game, or rent it.

stop selling it and buy it. install it to see if that helps. it kind of sucks that if it does crash again.

I still haven't beaten the game either. I stupidly created a character in between a fighter and magic user, so I'm not good at either. The only thing I'm really good at is making potions. I can make a bunch of invisibility potions and get through oblivion gates in a really sloppy and half assed way by using a lot of saves and just making a break for the sigil stone. Kinda sucks tho because I really don't like playing like that. I looked back at my achievements for that game and there is a one year gap between some of them.