Locked Vista business

Hi, have a masive problem with Vista business. I cannot install programs
or run files direct. Existing programs work fine. If I try to run a file from usb or
any other sorce I get the "file not found" error. Admin tools don't work either.
I done a boot scan for virus and once I got in and did the sfc command, but both
came up negative. The vista business dvd could not find a windows installation, so I aborted he repair. I'm puzzled what could be wrong with Vista.
Many thanks for helping me.

Welcome
Lets make sure that the obvioius causes can be eliminated.
You must do a full and upadated scan with your antivirus. It should take about an hour or so on average
You should download and make a full and upadated scan with malwarebytes.
If these come up negative try with a clean boot.
http://support.microsoft.com/kb/929135

Hi, first I thought my machine was hijacked, not hte case. Done full virus scan from boot. Have McAfee running (fully updated). Have also running spybot. None comes up with viruses or any other stuff

Trust me, use Malwarebytes, it may be negative, but many have thought that it would be and it was not.
Then do the clean boot.

You mention a clean boot, if you mean a "safe boot", it does not work I gets stuck at crcdisk.dll. I manually replaced the file, but no good.

Do the malwarebytes, then read my first post, again.

Are you the Admin or part of the Admin group?

Many thanks for the help. I could not run your virus scanner, the system keep replying "files not found". I try to fun safeboot with command prompt and it stopped again at the crcdisk. I end up pressing all the F-keys and all of a sudden I ended up with the command prompt and did a clean boot and a Restore. Worked perfect got my system back, have still no idea how and why I got past the crcdisk crash.
Again many thanks for the help

You are very welcome Austkeg, glad that it all worked out. Now go and enjoy.