what is User32.dll and is it a malicious file

[pophy_blesin]

the file is in system folder, so I think it should be a normal system file. But every time windows starts up, it will quickly freeze up. I opened Task Manager and found User32.dll took up 89% CPU. It is certainly not normal. I want to scan the computer with my antivirus program but the computer is frozen. Could I end the User32.dll? How to fix the problem?

[galeck1947]

Start your computer in safe mode by pressing F8 during boot up then run your antivirus scan to see if you have an infection also I would download and run Malware Bytes to see if there is any malware present and remove it as well. A virus infection wil consume a lot of CPU usage.

[Huderon]

Instructions for fixing the problem are at http://support.microsoft.com/kb/142676 - but it's a good idea to do a virus and malware scan as well