Hello Welder284,
Welcome to the HP Forums, I hope you enjoy your experience! To help you get the most out of the HP Forums I would like to direct your attention to the HP Forums Guide First Time Here? Learn How to Post and More.
I understand you are having issues getting your Wacom Tablet installed on your HP Compaq Presario sf5450f. In order to help you at all I am going to need additional information on your Wacom device such as what model it is. I am not familiar with the Wacom products myself, but I can attempt to locate any instructions or drivers that you may have missed. If necessary we can reset your computer back to factory so as to rule out any operating system issues as well.
You can reset your computer back to factory by first following the HP Support document: Backing Up Your Files (Windows Vista), which will ensure your personal files are backed up as they will be lost during the process otherwise. Next, after your personal files are backed up successfully, you can follow the HP Support document: Performing an HP System Recovery (Windows Vista), which will walk you through recovering your computer back to factory settings.
Once you have completed the above you can install your Wacom device.
Again you can also provide me with the model number and I can attempt to find your drivers and instructions first the choice is yours. Thank you for posting on the HP Forums. Have a great day!