Device Driver wont load ?

Hi. I have a communication problem with my HP 720c printer. It just stopped working, after changing my cable configuration.It is now directly linked to my computer. Question:
1)When loading the driver,it wont load the driver, and my computer cant find the printer port. It is on LPT1
2)How do I go about figuring out what the real problem is..IE: cable…card..printer..or ?
3) I have checked everything, and it all looks good physically.
4) I have restarted my computer to many times already, so do I need an instrument to check my hardware or is there a software program I can use to check these things?????
Thank you,
Pat