maybe a malware trying to open it ocasionaly, run good antivirus like nod, or kaspersky
there is an easier way (I remember seeing solutions during the whole 'coldzera afk on mirage' fiasco, but I don't remember them so...)
Do you have Microsoft Office installed? This happened to me a few months ago and something related to Office would open up randomly--got fixed in an update though.
check windows update to have the latest version, i think they fixed that
Don't click on hltv links dude