Need help with default xfce theme!

I installed Xubuntu 12.04, before I had Mint 9 Xfce. I didn't format my home partition, so my settings were preserved. The problem is that now my Xfce desktop doesn't look like it was in a live cd environment. The windows and their buttons look different, while it's supposed to be simple grey color, you could see it in a screenshot of xubuntu 12.04
It also happened when i upgraded from Mint 9 to 10 with the same home partition. I believe this is because of that. I tried to change appearance settings but none of the themes gave the result. What files should i delete or modify to get back the default look? Maybe I could copy config files from a fresh xubuntu install made on Virtualbox? I really need some help. Also it would be good to know what Lxde cofig files are.
Thank you.

try here ... you could always create a new user which should give you defaults

Thank you. I solved the problem simply by downloading and installing Greybird theme.