synth sound like this one

Sounds like a pretty basic 'strings ensemble' patch. I don't know nothing about no Joe Satriani or what equipment he might be using, but if I had to guess I'd say it was a preset off of a Korg/Kurzweil/Roland workstation-style keyboard, and it's possibly sample-based but shouldn't be too hard to replicate with a basic virtual analog. You'll need one with preferably three or more oscillators per voice. What synths do you have at your disposal?
 
It sound more like kinda slightly detuned supersaw that tend to sound a bit like string ensemble if detuned right and with right voice count.
 
thnx guys, do you suggest any vst that can do that? free or commercial, doesn't matter.

Arturia's CS-80V. The original Yamaha CS-80 makes the best string sounds (almost all of the non-acoustic sounds on the Bladerunner soundtrack were made with this one massive synth) and is pretty easy to program as far as synths go, at least compared to the painful menu-based stuff from the 80s or something relatively more complex like Absynth or Reaktor. There might even be a preset on the CS80V that's pretty close already; I would imagine the majority of the presets are strings and pads. It looks like they have a 15-day demo for download, so go hog wild.
The key to a sound like this is detuning the oscillators a tiny bit with respect to each other; it basically acts as a chorus effect and gets that thick, swirling sound. There's also a bit of glide/gliss/portamento on the patch (that "sliding" thing from note-to-note) and some performance stuff like the obvious pitch bends. And reverb. Boy howdy, there's a lot of reverb on that line.

Otherwise, you could find some strings samples (look for "ensemble" patches) and mess with those. Again, this sound could feasibly be sample-based - it's tough to tell in a mix, doubly so with these cheap-ass earbuds that I use at work - but you can certainly approximate it with a poly synth and that's more fun anyway.
 
Arturia's CS-80V. The original Yamaha CS-80 makes the best string sounds (almost all of the non-acoustic sounds on the Bladerunner soundtrack were made with this one massive synth).

No, it doesn't. Trust me on this. The strings on BR are from the Roland VP-330, then there's Rhodes, Yamaha GS-1, Prophet-10, Emulator and a bunch of other stuff. CS80 does the brass/horns, the flute-type sounds, the harmonica, some (most?) of the weird clangorous ring-modulated sounds.. Once you learn how it sounds, you can start to hear it's "signature".. ;) Although it's played on the Yamaha GX-1, Stevie Wonder's Pastime Paradise's strings are pretty close to what the strings sound on the CS80 (as it should, since it's a direct descendant).

Back OT, there might be a layered "synth" strings in there to give texture, but most of it I'd say is sample based primarily.
 
The strings on BR are from the Roland VP-330, then there's Rhodes, Yamaha GS-1, Prophet-10, Emulator and a bunch of other stuff

I just looked up some articles and you're right, and the nerds who edit Wikipedia have lied to me for the last time :err:
Wikipedia said:
...This can be heard on the Blade Runner soundtrack by Vangelis, in which virtually all the sounds are created from the CS-80.

Anyway, I just threw out the first synth that popped in my head that had all the necessary ingredients for a fairly simple strings patch such as this (multiple oscs per voice, detuning, glide controls) and that also exists in VST form. I kinda stopped paying attention to other VST synths after buying NI Komplete but I'm sure there's some good new stuff out there too.

edit: I submit that these strings rule @4:45 and especially @ 5:36. Not what the OP's looking for but I want one. [ame]http://www.youtube.com/watch?v=sJNn3gKxdsA&t=5m36s[/ame].