I don't have HCE, but it sounds to me like you need to install an opening book in it.
Problem with HIARCS Chess Explorer
The opening explorer window certainly lists book moves for it, but I don't see any evidence it uses them.

Did you try to contact HCE support?
I opened my HCE and had it play white and got e4 half of the time and d4 half of the time. Playing e4 for white always got c5 in response.
At any rate, their support is probably the best way to get the answer you want.
my 2 yen.

How odd. For me, it varies, I have several options of its style of opening play (tournament, dynamic, wild), and can even view the % of times it will play a given opening if left to its own devices (For example, as White it will currently play 1.e4 36% of the time, 1.d4 36% of the time, 1.Nf3 18% of the time, and 1.c4 9% of the time).
I have the iPad version though, so maybe it is different.
I just got HIARCS Chess Explorer. Looks good, except that it makes the same opening moves every time? Always Nf3 with white and d5 as black against e4.