program crashing randomly code -1073741819

[feraudyh]

Hello,
I have written a Windows XP Qt app and it occasionally crashes when it tries to connect to Postgres.
There are several ways it crashes, sometimes the main window closes and other times I get a more polite message box before it crashes.
I tried putting in a trace with QMessageBox::information inside various parts of my
"dbConnect()" function, but it has always worked when these have been enabled
(to remove them I used
#define TRACE()
)
I have never seen it crashing inside the deebugger either.
I'm wondering about how to go about hunting for my bug.

I've heard that there are programs like Rational Purify and Valgrind
that could help me point to the error, but I'm running on a small budget.
What do Qt developpers do, apart from looking at their code very carefully?

By the way the last time it crashed it left an error code inside Qt Creator:
-1073741819