No monitor branch in device manager

First thing, I know next to nothing about computers.
We have a problem with our monitor switching off after start-up. The only way we can turn on the computer is by disabling the video card (Radeon x1300 pro).

Last thing that we did before the computer stopped working was to load suggested Windows Updates.
"Windows Malicious Software Removal Tool - August 2009 (KB890830)
Update for Windows Mail Junk E-mail Filter [August 2009] (KB905866)
Security Update for Windows Vista (KB973540)
Update for Microsoft Office Outlook 2007 Junk Email Filter (KB972691)
Security Update for Windows Vista (KB973507, KB971657, KB971557, KB956744)"

We have tried updating the Radeon Video card which is now updated.
We tried re-installing the Viewsonic monitor wizard cd and it said that we had to manually install a component (display optimization files)for Vista but then it wouldn't complete the installation. The viewsonic file in program files is there but empty.

Now I've found that the Monitor device in Device Manager is gone so I can't try to enable or change anything to do with monitors.
Help!!

I have no access to another monitor to see if the problem is with the monitor itself.

Just wondering if I should spend the $200 on a new monitor or getting the computer fixed by tech guys?:huh: