They got the vundo trojan, as well as a few other things.
Uninstall anything to do with Viewpoint.
Download the trial version of
Spy Sweeper from
Here
Install it using the Standard Install option. (You will be asked for your e-mail address, it is safe to give it. If you receive alerts from your firewall, allow all activities for Spy Sweeper)
You will be prompted to check for updated definitions, please do so.
(This may take several minutes)
Click on
Options > Sweep Options and check
Sweep all Folders on Selected drives. Check
Local Disc C. Under
What to Sweep, check every box.
Click on
Sweep and allow it to fully scan your system.
When the sweep has finished, click
Remove. Click
Select All and then
Next
Exit
Spy Sweeper.
Then reboot and post a new Hijackthis log and we'll get anything left.