Hello. I have the following problem: when using any functions of the context menu something like virtual sticking of the ALT key occurs. That is, I click on object by RMB and select some action with the object from the context menu, then after that if you click on the object using LMB or ENTER, its properties are opened instead of opening it. Bug appears periodically and only after using the context menu. P.S.: I checked for suspicious programs and cleaned Autorun - everything is clean, checked the disk and system, chkdsk & sfc / scannow, for integrity - everything is fine, the mouse is configured correctly, the keyboard and mouse was changed couple of times - it didn’t help, reinstalling the OS - it didn’t help, the OS is clean not assembly, reset BIOS settings - did not help. Temporarily bug removes pressing the right ALT key. I read that this may be a problem with the motherboard. I noticed that for the most part this bug appears when scanning objects through the context menu using ESET Internet Security 12. After scanning through RMB with this antivirus, when you click (LMB or Enter) any object opens its properties instead of opening it. The bug is removed only by pressing the right ALT. After that, everything opens normally. System: Windows 7 SP1 X64 Ultimate. Clean image. Tell me, please, what could be the cause of this bug, how to check the motherboard, and other PC components, the cause of this bug, or another way to solve it? Thank you in advance.