Hi Frank,
We are sorry to hear about the trouble you are facing with Illustrator. That's definitely not a usual behavior. Chris has very well described all the possible reasons. In addition to that, I would request if you can share a few more details like:
- OS (Windows 7/10)
- Are there any recent changes made to system? For example, any antivirus or web extensions installed recently.
- Which graphic card is installed on your system?
- Try booting the system in safe mode and let us know how it works there?
To boot system in safe mode check out the steps shared in the links below:
- For Windows 10: https://support.microsoft.com/en-in/help/12376/windows-10-start-your-pc-in-safe-mode
- For Windows 7: https://support.microsoft.com/en-in/help/17419/windows-7-advanced-startup-options-safe-mod e
Looking forward to your response!
Regards,
Srishti