Instup.exe is a component of Avast's antivirus software and is required to update the application. It is downloaded to your computer along with other files when you install the antivirus. In other words, it is a legitimate file that should not harm your computer. However, this is not the case and many users complain that the instup.exe file causes performance problems in Windows, namely, x up to 100% of the CPU resources. This, in turn, makes the applications unusable and makes it difficult to use the computer as a whole. This article will save you from this problem and will clearly show you how to prevent the file from affecting computer performance.