[Help!] VST instruments/MIDI tracks won't play .... no sound

[klackt]

Hey guys, nice to be on the forum..

I'm having a bit of trouble and I really need some help! I'm new to Ableton..

So, I've been working on a set, and recoreded some sounds, played with my MIDI controller with a few vst instruments. However, I went to adjust somethings in the Session view, and now when I got back to Arrangement view, and try and play the instruments with my controller or my qwerty keyboard, there is no sound coming...

However, if I start a new session....all is fine!

Please help!

Thanks!

[NPC]

1st: welcome aboard klackt!
2nd: if you're new to ableton i suggest starting to emphasize the session view-this is where the fun is and where live really is years ahead other DAWs-but that is just a personal suggestion..most people actually use arrangement view a lot.
3rd: i guess the problem is something related to changes you do when in session view..youre probably tweaking something that prevents the instruments to be heard after that..but they're probably still playing, so dont worry. when you tweak something right after you loaded the set-so the inst's are playing- as you move the first knob or whatever you'll see a red button in the upper center of live's gui turning on:that means "back to saved" (sorry now i dont recall the exact label)so if you experience problem caused to tweaking -that is, a thousand times i just put a filter in a synth all its way to zero, or something similar-by pressing that button every parameter switchs back to its saved state, so everything should play as when you loaded the set..
hope its useful..cheers!