Need help! Solo Track function broken? (newbie to PT)

[Bonetones]

So I have Pro Tools 9.0.3, I'm learning my way around with the help of this forum, video tutorials, the manual and books and I started a session 2 weeks ago...
Yesterday, i went to record some tracks and when i went to solo said tracks...nothing...complete silence, in fact, i can't solo ANY of my tracks! The solo button works visually and mutes all the other tracks like it's supposed to BUT there is no audio whatsoever. i checked everywhere i could think of, it's not solo-safed, i've tried all the troubleshooting i could think of, any help would be appreciated. I even tried starting a new session and importing everything into the new one thinking maybe something got corrupted in my old session but no luck.
Plus, i seem to have to trash my preferences and "reboot" PT a LOT! (it will randomly take forever to load and then get hung on "building edit window")
but sometimes it loads up lightning quick, is this normal?
I am quite meticulous when it comes to permission repairs, optimizing my system, saving and backing up frequently just FYI...
Thanks again to anybody who responds

[Bonetones]

sorry, i forgot my tech info: (thought it would show up automatically)
MBP 15" (late '08) 2.4 GHz Core 2 Duo, 4 G of RAM, MOTU Traveler, 10.6.7, PT 9.0.3. Glyph GT050Q FW800 HDD, Frontier Designs Tranzport, Novation Remote SL 61 with Automap 3.7

[BobbyDazzler]

Are you using any busses or submasters that need to be in solo safe?

[zcherries]

Is your audio going through a bus? And if so, is that bus solo safed so that audio can pass through it when tracks are soloed? Either that, you need to group the bus along with the tracks your soloing so that audio will pass through it.

[Bonetones]

I actually have all of my tracks bussed to a headphone mix (via sends) at this point AND a submix (which i use for muting the mains while tracking). I thought that I checked the solo safe function but I sheepishly admit that I didn't think to solo safe both of them, when I did that, voila! everything's back to normal! Thanks a lot you guys, I appreciate the help, I thought I understood the "solo safe" function but apparently I don't! lol (and apparently i needed to use it even though I didn't think i needed to) Thanks again, time to get back to it, i really do love Pro tools when it's working! lol