hey.. registered just to post about this!!
i got my vx2268 last week, and i have the exact same problem as you.
Our only similarity is that i didn't install the CD (because i lost my SATA cable for my CD drive.. no idea how

)
But anyway, i was trying to run games at 120hz and it was jolty.. less smooth than my old 60hz monitor. Then when i rebooted the next day i had those vertical lines, and i've since had them at 100/110hz etc
So there's a strong chance that the drivers from the disc are like no other (but my friend with the monitor says he didnt even use drivers =/) or the monitor just feels like it's being forced at 120hz.. which is a bit naff
I ordered the samsung 2233rz a few days ago anyway (hasn't arrived due to snow - thanks parcelforce), and ****** are collecting the viewsonic and "say" they will refund me.. but they didn't even ask about the fault.. so we will see, i sure hope they do.
Cya around guys