I've just purchased a new computer and I'm installing the Police Quest 1+2+3+4.

When I load PQ1 from the desktop icon, it loads the VGA version. How do I load the original version of PQ1?

If you've installed the whole pack there are two desktop shortcuts for PQ1:
Police Quest - In Pursuit of The Death Angel
Police Quest - In Pursuit of The Death Angel (VGA)

There are also two separate installation folders for the original and the VGA version:
..\Police Quest 1-2-3-4\Police Quest 1
..\Police Quest 1-2-3-4\Police Quest 1 VGA

Inside each of them is another shortcut ("Launch Police Quest ..") to start the chosen version, just in case you're missing the desktop shortcuts.

If there aren't both folders, the original version wasn't installed. Re-run the installer, select "Options" and make sure the versions you'd like to have installed are all ticked.

Thanks DeMignon

The problem was that I didn't have the latest setup file.

I posted this an hour ago and it didn't show up so I'm trying again.

You're welcome. It happened to me as well a few times, that there was an issue just because I had installed the game with an archived outdated GOG installer. Now, I usually download the current version before installations or at least when there are any problems with running a game. Re-installing can work wonders ;-)