So I was playing Oblivion, I saved my game and exited the game and went to do something else. Then I opened it up again, tried loading, it loaded it for like half the bar, then it crashes and windows says it's encountered an error and the software has to be closed or w/e. I tried opening it several times with and without shivering isles, sometimes it loaded almost the whole bar but still crashed.

What to do, I don't want to lose my 15 hours of gameplay.

Unfortunately it sounds like your save has become corrupted, nothing you can do.

If you rely on quick saves, auto saves or overwrite the same save constantly this can be a common problem.

Alright well I think I have a save from a few hours back, I'm wondering if I can use it or are all my saves corrupt?

Is there anything I can do to prevent this from happening again.

It may be ok, best thing to do would be to try.

for prevention, turn off all auto save options, don't use quick saves and keep as many different saves as you can, best to make a fresh save than overwrite an old one.

Saving while taking damage is another thing that is known to cause corruption, such as vampire sun damage or a duration spell. I personally never save while there is any active effect with a timer on my character.

Ah, that's it, I went to bed and woke up as the "level 2 vampire", I went out to find that I take damage from the sun, I saved, went to find out how do I cure myself, tried loading back and the file was corrupt.

I had a save which was done only 15 minutes before the corrupt save, which works, so yay! I'll turn autosave off now.

Thanks for the help! Appreciated.