Since some software could generate louder sound than other software, I knew the speakers in my laptop were capable of generating loud enough sound. I did a quick search on the web for
"laptop sound software amplifier" and indeed I found one.
There may be others that do the job equally good, or better, but this is the one I installed, and briefly tested with Microsoft Streets & Trips 2009.
SX Fidelity Amplifier by Sound Genetics
http://www.soundgenetics.com
There is a trial version available to download. Try before you buy to make sure it does what you want. US$19.95 to register.
Installation was quick and painless. The software can start each time Windows starts, and it can be run minimized to sys tray, so a user just needs to configure it once and forget about it. It allows for up to 12 dB of amplification, which I though was very generous amplification. I was surprised how loud my laptop was! I suspect not too many people will have the need for the maximum 12 dB amplification.
I think $19.95 is a very reasonable price. It saves you from having to buy a set of external speakers, or an FM transmitter, or headset, or a new laptop with louder speakers.