Virus Ti Snow & Cubase 5

    Hi dear friends
    I have a problem with cubase 5. I have installed ultimate OS 4 on my pentium Dual Core Quad 9550 - 4 gb ram - 1 TB Hard disk - Sound Card M-Audio Ozonic Firewire.
    On my Snow at the start up compare the 4.0.0.18 OS but the virus control center don't go on pc!
    And if i want to create a project with cubase 5 the Virus Snow play only one track and not all 4!!!
    I have contacted the Access support and i have reinstalled 10 times the operative system but the results it's always the same.
    With ableton live suite it's all ok but with cubase no!
    It's there someone who want to help me to solve definitely this problem?
    I would want to know if i made error to set the Device Control or the VST Connection on the preferences of cubase or if is a problem of last OS.
    Excuse me for my english, i'm italian.
    Many many thanks