Right now I have a routine based on CPearson's OnTime running on my Excel.
But it does not really meet my requirement. It runs every 15 minutes of the
clock only if I start Excel before 8 am. If I start my Excel at 10:07, the
module will run at 10:22 followed by 10:37, etc.

I need my Excel module to run at every 15 minutes of the clock. If I start
my excel at 10:07, I want the module to fire up initially at 10.15 followed
by 10.30, 10.45, etc.

My knowledge of excel programming is rather basic.