Start from scratch with 360 XBLA games?

[crashwg]

I'm having trouble with Trials HD on my RGH 360.  I had everything working fine with just Trials and it all still worked with the first track pack "big pack."  The problem started when I tried to get "big thrills" working.  I dropped the folder in the proper content/0000000000000/etc folder and transferred a TU to the cache folder.  Booting Trials I got something to the effect of "big thrills corrupt."  I then removed everything in content/0000000000000 folder that had to do with Trials and started from scratch and used freestyle dash to get the TUs and now neither track pack works.

So my question is this:  Where else on the 360 is there stuff stored that might be messing this up?  I would like to go delete it and try it all again.

<edit>
I would like to keep my saves...
</edit>

[crashwg]

And where did I say that I don't own the game and track packs?