Hi Vesaarno,
• Any recent changes done on the computer?
This may usually happen due to data execution prevention.
Try adding it in the exception for data execution prevention and check if it works.
Step 1: Go to Start, Control Panel and click on System.
Step 2: Now click on the Advanced tab and under Performance, click on Settings.
Step 3: Click on Data Execution Prevention and select the Turn on DEP for all programs and services except for those I select: radio button.
Step 4: Now click the Add button and browse to C:\Windows\System32 and choose the regsvr32.exe file. When you get the message stating it could make your computer become unprotected and vulnerable to attacks, just click OK to continue.
Click OK and then click OK again to exit
If the above steps fail then I would suggest that you check in the event viewer to know the cause of the error and post back with the details from the event viewer.
What information appears in event logs? (Event Viewer)
http://windows.microsoft.com/en-US/windows-vista/What-information-appears-in-event-logs-Event-Viewer
Hope this helps!
Halima S - Microsoft Support.
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