I run Windows 7 Home Premium on my desktop upgraded from Vista. Some days ago out of a sudden my system doesn't work any more smoothly. The only thing I did were some deinstallations of programs and the installation of some downloaded programs - I did this under an account without elevated rights, though I was also prompted to give the administrator password which I regularly did. Here are the symptoms of my corrupted system : 1. If I boot the system and sign on an Installer process automatically starts. It refers to the Nitro PDF Profesional program ( which I also tried to install some days ago ). The dialog window disappears after some time without further notice. 2. Every installation of a program fails : I get a message box which says that the dirctory C:\ProgramData\Microsoft\Windows could not be created. 3. Now the worst : the Windows Update ends with the error message 80246008. I found that the BIST-service ( Background Intelligent Transfer Service ) can be found but isn't started what obviously hampers the update. If I start it manually it fails. The problem seems to be known since Vista times. 4. An application which I regularly use and which uses Adobe AIR fails to run out of a sudden. I could add screen captures of the messages, but they are in german language and so probably not helpful here. 5. I found a program ( recently installed ) which causes on startup the Installer to become active trying to install a program which is already installed on the system. A .msi file out of the folder C:\Program Files\Common Files\Wise Installation Wizard is activated and requests the administrator password. If I deny this, an infinite loop of Installer-starts begins. Is this system infected or destroyed by malware ? A complete scan for viruses and Malicious Software gave no hits. I also deactivated some programs on system startup but this had also no effect. May someone have left a nice "present" on my system ? I have the bad feeling that some uninstall program messed the system - this has disappeared from the system, so it can't be found any more. Or : is it really possible that the simple visit of an infected Web Page can be so harmful, even though I work as a normal user ?

Hi, These issues may occur by virus or other separate cause. If you would not like to troubleshoot them one by one, I suggest you perform a clean installation to get a new system which can be stable and quick. However, if you would like to address them one by one, please try the following steps. 1. Download Microsoft Security Essentials and install it on the machine. Then, please upgrade the virus definition and run a complete scanning. 2. Please refer to the following article to troubleshoot the Windows Update issue. Windows Update error 80246008 If BITS service still cannot be started, please let me know the error code. 3. Please run System File Checker (SFC) to verify whether any system file is corrupted. Thanks, Novak