I'm a Sibelius user; no sequencer, no MIDI hardware. New Creative SB 24-bit soundcard (which says nothing about ASIO on the box. What is ASIO?).
I just got my copy of GPO, which I've much looked forward to. Installation is proving to be the usual software setup nightmare, however. The prompts and instructions seem to have lacunae and discrepancies and assume considerable audio software knowledge.
I clicked all the boxes to install GPO, VST, Studio, everything. However during installation the system got to a point where it searched for VST, which is still a mystery acronym for me. Not finding any, it gives me a message that VST will be installed in Program Files\Vst...etc. I click OK.
But upon completion, there is no such subdirectory. I see a VST subdirectory in the main Garritan directory, with a 19MB file in it -- is that the VST plugin? The manual instructs "First ensure that you have installed the VST plug-in version of GPO..." but does not say how to do this.
On GPO Studio, I don't find this anywhere. I search WinExplorer for "studio" -- nada. How do I find out if it was installed? P. 42 of the booklet says to click GPOStudio.exe on "the disc that came with Personal Orchestra." Which of the three discs? It isn't on the first one.
ASIO is basically a soundcard driver which gives minimal latency (time between hitting a key on a keyboard and the note sounding). My SB (live and audigy 1 and 2) boxes all have ASIO written on them - not sure which model you have?
VST is a technology Steinberg invented to enable software synthesisers and effects to be played within a midi-sequencer (like Cubase). GPO can be a VST instrument inside a sequencer if you wanted it to be (hence allowing you that install option). If Sibelius can't use VSTs then it doesn't really matter where the VST is!
GPO Studio can be found on Disk 4 of your GPO set of 4 disks and is installed from there.
Sibelius works with GPO, but not via the VST format. To work with Sibelius you will need the GPO Studio v1.2 which, if it wasn't shipped with your copy, is downloadable from the Garritan site. The way it works is you open GPO Studio before opening Sibelius and it will run in the background. Sibelius will recognize it as a MIDI playback device and allow you to select it when you set up a new score. You load up the instruments you need in GPO Studio and then make the corresponding selections in your Sibelius mixer. I know, you're probably thinking "What?", but it really is quite logical.
GPO Studio v1.2 allows you to record to wav, which is a great feature since the record to wav function in Sibelius only works with the Sibelius Kontakt Silver or Gold players and nothing else.
Good luck as you discover the ins and outs of setting up and using GPO. It took me a while but I found everyone on this forum to be quite helpful.