Warcraft III:The Frozen Throne Problem Please Reply and Help me :(

[warrockReborn]

Hello Im a DotA Player I play DotA at Garena,whenever I play DotA On-Game sometimes (almost always) it automatically leads me to my desktop and I need to Alt + Tab to go back to my game,but the game is not harmed and nothing happens it only gives me a little lag,but after I control my hero (character) and move it around the lag is gone.I have an antivirus,in fact I have 2 of 'em • Eset Smart Security 4 • Malwarebytes' Anti Malware.They are both always updated yet the automatic alt + tab occurs I hate when it occurs !!! When I'm clashing with the opposite team I get killed because of what is happening.So Please Help me .

Thank You

Additional Details:

•If it's a spyware or something,I don't how it got in my PC,my Anti-viruses are at Full Protection and has an Anti-spyware