Start Virtual PC. Either double-click the icon or you might have to right-click it and choose "Run As Administrator" on Windows 7.
If you have a Windows 95 or 98 VM (Virtual Machine) you've never used with Virtual PC before, you'll first need to add the VM to Virtual PC.
File (in the Virtual PC toolbar)
New Virtual Machine Wizard
Put the radio button next to "Add an existing Virtual Machine"
Click the Browse button.
By default, Virtual PC looks in the "My Virtual Machines" folder. You browse to wherever you put the VM folder, look inside the folder, select the .vmc file (ends with the extension .vmc), and click the Save button. Keep going and once you've clicked the Finish button, Virtual PC should list the VM.
To start the VM, you can right-click it where it's listed in Virtual PC and choose Start -- or you can highlight the listing for the VM and click the Start button over on the right. If your computer has no floppy drive and the VM is configured to use one, you may get some message about the VM starting with the floppy disconnected. This is fine.
Once the VM has booted, insert your game CD. If this particular game has no autorun on the disc, or if autorun is disabled in your VM, use Windows Explorer (or My Computer) to browse to the CD drive and look for a Setup or Install file to double-click to start the installation.