let's get small
If you can't find the model of your Compaq computer written on the outside of your system unit, all is not lost. First, try pressing F10 when the Compaq logo appears while the system is booting. Look for the Asset Tag which includes the model number. If that doesn't work, try to download and install the latest Windows Diagnostics. At the moment, the latest diagnostics seem to be PC-Doctor 5 for Windows Diagnostics Update.