It just say's loading add on's and does that for ages but the music still play's playing on xbox 360

Try clearing your cache and letting it update again. There could be a corruption, for some reason.

You can also press and hold the "RB+LB+X" buttons whilst the game starts.

Edit: fixed an error on my part.

Won't that delete all my saves on my console will I have to put everything on my hard drive and hearthfire works good but all three together makes it loadfor ages

No. Clearing your cache only deletes the patches(which are stored apart from your actual game and DLC files)

your save files are left alone.

So I will not lose any other stuff then just patches for glitches

Everything will remain the same, the only thing being deleted are the patches(bugfixes, etc)

If you're feeling unsafe on how to perform this, visit this link:

http://support.xbox.com/en-US/xbox-360/system/clear-system-cache

After that, once you start up Skyrim, it asks you to re-install the patches.

So say if I wanted to clear my hard drive cache I would still have my achievements and save games

You keep it all. As said, the only things being deleted are the patches.

But if you don't feel safe doing this, try using the other option:

Press RB+LB+X whilst Skyrim loads. This does not involve you getting into your system settings, so this might be a better option.

I just cleared the cache now can I install the dawnguard and dragonborn

You already has the DLC's installed right? They will be still there. You only cleared the patches(more killcams, horseback combat, etc. Which will be installed as soon as you boot up the game)

If you had no DLC installed, you can install them, yes.

I installed them now and it [censored] works bro you genius

I wish I were a genius :c Nice to know it worked, though. Now you've learned an important Skyrim survival tip.

Only patches that are 6mb or less get deleted when clearing the cache, the Skyrim title patch is 26mb so it will not be deleted when you clear the system cache but that is only if it is stored in your memory.... For some reason when you first install the LE, the 1.9 patch is not installed in your memory and will get deleted the first time you clear your system cache.