Hello Trash Man,
Basically, when you put a file in the recycling bin, the file doesn't actually change location on the hard drive. All that changes is where the directory entry for that file is stored. It is now stored in a hidden and protected system directory called Recycled/Recycler. When you delete the file from the recycling bin, the directory entry is removed from the Master File Table (MFT), but the file information remains on the hard drive. Often after this point, and a potentially considerable time elapse, the file is overwritten by other file information. So with the right utility, the file can be retrieved after deletion from the hard drive.
More information can be found
here (geek girls, gotta love it!).
You can use a secure erase utility such as
Eraser, but be careful as these tools are powerful and can erase whole hard drives. Make sure you read all instructions on the website prior to attempting use.
To the best of my knowledge, the answer to your second question would be no, the flash drive has its own storage area and should not transfer file data over to the computer's hard drive without you knowing it.
Seeking to satisfy your desire to obtain knowledge is never lame! On with the endeavor Trash Man!
Cheers,
Ax
Edited by Ax238, 10 November 2007 - 12:03 AM.