Taskbar and desktop appear, disappear then vanish

I know I posted on this before, but I am wondering if this could be a virus?
It is just on my account, because my sister's account works fine. I will log
onto my account, and my webroot spy sweeper will pop up, eventhough I swept
my computer twice. Then, the taskbar and desktop icons will appear for about
a minute, then disappear, then appear, then disappear almost like it is
refreshing itself. Then, they both just vanish permanently. I have done a
system restore and nothing happened or got fixed. I swept my computer almost
5 times and nothing has been detected. Is this a virus? If so, is there a way
to fix it? I'm just confused because it doesn't happen on my sister's
account, just on mine. If anyone can help, Iwould appreciate it! Once again,
sorry for posting yet another post.