Well pwiz siad some thing about windos live on vista i dosen't play nice with tre if this happens and the game still have a bar on the start bar alt tab back to the game
I have windows live w/ VistaUlt32, no problems here... but if that is the case for the member, and it is WL, I would recommend checking the firewall(s), as I have noticed RA3 often interfaces with the internet, RA3 might be a blocked program, same happens with the trainers from CH, every time you update it, you have too allow it again, as the nature of the program has changed since you last exempted it from blockage.
So long story short (too late), check your exceptions and blocked programs... and of course, run the program as an admin, by right clicking the .exe icon, most likely on your desktop... and then set it to "Run as Administrator."
Hope this helps and if it doesn't, drop us a line.
Nem'