Hi! I am a fairly new to Android and have a question about where the .apk files would be stored on a Samsung GT P-1000?

I have downloaded and paid for a number of games that I would like to delete from my tablet but keep a backup on my computer. Kies doesn't seem to look for these files so I decided to find them by directly by hooking into my PC and searching. I have done a search on both my SD card and Phone icons but have only found a few files with .apk and they are not my games. What am I doing wrong???

Any help would be appreciated.