ALT key locks my computer or sometimes shuts it down!

as the tittle says, when i press ALT key (no matter left or right) it just turns my display off, the power button light on the CPU goes off, when i press the power button it takes me to the lock screen.. no startup animation (Motherboard info, Windows startup animation ect). i click my user to unlock it and it has closed all my programs like its just rebooted its right there where i left it actually... please help! i use ALT TAB a lot and this thing is bothering me!

EDIT:-
my rig

i3 3220 Processor (not overclocked)
Gigabyte H61M-S1 Motherboard
8 GB DDR3 Memory
GT 610 2GB DDR3 Graphics card from zotac
450v PSU

EXTRA INFO

i did a fresh install of windows 7 last week and this problem started yesterday, never encountered this problem ever!

Have you tried another keyboard?

You can open the On-Screen Keyboard built into Windows.
Start > on-screen....

Click on Alt on that virtual keyboard and see if the computer does its weird thing.

It sounds like you could use a new keyboard. Maybe you can borrow one to use for a while to confirm that a new keyboard will solve the issue.

UsernameIssues said:

It sounds like you could use a new keyboard. Maybe you can borrow one to use for a while to confirm that a new keyboard will solve the issue.

well buying/borrowing a keyboard isn't a valid solution, i just went to safe mode and alt key was working normally.. cant i do something to find out what actually happens when i press alt?

You can try these steps:
Troubleshoot Application Conflicts by Performing a Clean Startup

UsernameIssues said:

You can try these steps:
Troubleshoot Application Conflicts by Performing a Clean Startup

i did a cean startup, didn't worked.. i think i'll just install windows again from scratch. thanks for help!

You are welcome.

I have asked other forum members to join this thread.

Process Monitor might tell you what app is making the computer go to sleep when you press the Alt key. You might need to set it up to write its info to a log file rather than keep the info in virtual ram. (On the Menu bar, select File > Backing Files...)

start gathering data via Process Monitor
watch the seconds on the computer's clock*
press the Alt key at some time like 15 seconds after some minute
after you wake up the computer
stop Process Monitor from gathering data - if need be
look for events near the exact time that you pressed the Alt key

Since you are interested in Process and Thread activity (when stuff starts), you can filter out registry, file and network events via buttons below the Menu bar. Mouse over each button for a tool tip.


* I use an app that shows the seconds. You can open the applet that lets you adjust the system's time.

UsernameIssues said:

Process Monitor might tell you what app is making the computer go to sleep when you press the Alt key. You might need to set it up to write its info to a log file rather than keep the info in virtual ram. (On the Menu bar, select File > Backing Files...)

start gathering data via Process Monitor
watch the seconds on the...

i got no idea what did that but the screenshots shows when that happened

EDIT:- what should i search for to find out what made it go to sleep?