I'm not sure what cpu/gpu mining is.
CPU (central processing unit) is the thing in your machine that does all the work. The GPU (graphical processing unit) is pretty much the same but specialized on graphics and thus better for certain tasks than your CPU. E.g. for rendinger computer games, hashing or mining bitcoin.
I am using an S1
The S1 however is special purpose hardware (called ASIC) that is very good at a single task. This one is good at hashing sha256/mining bitcoin, it can not mine any other coin that is not also using sha256. E.g. it can not mine litecoin, because litecoin uses scrypt.
with the software GUIminer in slush's pool and the popup window for the GUIminer has at the left on the bottom - shares:19 accepted (which changes)
Thats basically the number of tasks your machine has completed.
and on the right is has 17.1 Mhash's (which changes between 16 T0 17) . I was guessing the 17.1 Mhash's if the speed, am I right and isn't that slow?
Yes MHash/s is the speed, but 17 MHash is something your CPU or an old/mobile GPU would get[1]. The S1 should be hashing @ ~180 000 MHash/s or 180 GHash/s. Thats why I asked whether you are sure that you are mining with the S1. Does the Guiminer actually know about the S1 and is it able to use it?
[1]
https://en.bitcoin.it/wiki/Mining_hardware_comparison
