A Soft Reset can be done by holding down [Alt] and [Num] and hitting the [Del] key (where [Alt] is the bottom key in the left most column of the keyboard, and [Num] is the bottom key in the second from the left column, and [Del] is typically the second key from the top in the rightmost column).
A Hard Reset is a Battery Pull. This can sometimes also be done by using the [Alt][Num][Del] twice in a row, but the battery pull is more reliable. If the device doesn't sit with the hour glass for at least a few seconds (up to 30+ on some devices!), and do a full security scan of the software, you don't have a hard reset.
These are NOT the same as a power off / power on cycle. I've seen situations where a power cycle doesn't reset the device - it just comes up with the same problem, and I've seen situations where a soft reset doesn't clear a problem and only a Battery Pull works. Just to confuse the issue more, my 8800 comes up with two power off options - Turn Off and Full Power Off. I don't see much difference between the two though!
Just time how long the device takes to come up (especially on a 7100!). You'll see that the power cycle is fairly quick, and the soft reset is not as fast, but quicker than a battery pull!