My understanding of how the WOT client works, nothing is maintained on you local PC other than caches -- meaning, your stuff should still be there you just cant see it. This is evidenced by virtue of logging into you account from a friends PC and your stuff shows up.
Have you tried loading WOT onto a completely separate PC, logging in, and seeing if in fact your stuff shows up in your depot?
Only way to empty your depot is to sell your stuff -- and I assume your bank account is not larger.