server 2008 - task Scheduler - send mail where file size > X

server 2008 - task Scheduler - send mail where file size > X

I have a software that create log files. I search a simple way to send an
email when the last file created is bigger than 5ko (logged error(s)).
I was looking at the task scheduler. He can trigger each day at X and send
email. But for the size I dont know how to do it.
I look at bat file but I probably need installation of something for
sending email. It can be also in powershell script?
whats the best way to do it, preferably without any installation, only
create a task and put a file somewhere. (I have restricted right on the
server)