cubase sx2 line in problem posted by ...

hey guys i'm new here.
here's my latest boggle....

okay i'm using vista and cubase sx2,
i've been recording midi files easily enough (not on a keyboard, drawing with my mouse), but when i try to record an audio file, it ain't happening.
1 of 2 things happens when i try...

1) i plug my guitar through a boss gt-6 processor, line out of the L mono output and into my pc's line in (have tried the microphone input too, same result)
this way, i can hear the guitar through my pc speakers, but when i try to record it, cubase doesn't record it, the signal doesn't even show up in cubase.

2) i bought (borrowed thnx ciaran) a behringer usb thingy that i plug my guitar into, it's a ucg102, and i installed the drivers / asio for it.
now i get the option to change to the behringer usb audio asio in the vst multitrack in cubase, instead of the default asio i had been using.
so this allows me to record my guitar parts onto an audio track in cubase, problem being, the behr asio won't support playback of my midi's (or audio recorded with the usb device) so i'm effectivly playing deaf, then i gotta switch back to my default asio again to hear what i just recorded which is alway off time....(no matter how hard you try, u can't play an imaginary click in ur head lol)

okay so that's my problem, wanna record audio, and be able to monitor it and the previously recorded midi with sx2.

i should point out that i was using a different p.c. before, never has any problems with it, was simple, plug in to the mic input and play away, cubase just doesn't seem to recognise the audio i give it as audio, i don't know if it really is a driver problem ( i tried asio4all no help).
anyway , any help on this topic would be greatly appreciated, i've had my pc for 6 months now, and STILL can't use it for what i wanted it for
thnx,
muck