Okay, when you look for the driver, look up the specific type of digital camera you have, then go to Canon and look up the driver for that one. If you can't find one at canon, go to
http://www.driverguide.com and join (it's free) and then they will send you a password in your email and you can go and look on there. They will generally have what you need if canon doesn't.
When you look for the driver, make sure it is compatible with your OS (windows 98, windows me, etc)--that's very important.
If you have windows me or xp, a lot of times your pc will find it for you. I can tell you how to do that if you let me know you have either of those OS's.
You will need to reinstall the driver for your camera. Now as for the software for the camera itself, if it's plug and play, you can (on some of them) just plug them into the pc and turn on the pc and see if it recognizes the camera. If it does, then you can have the pc look for the driver. If it doesn't, then you'll have to find one yourself.
If you have problems after trying my advice

Then list your os and your device specs here and I will go and see if I can find your driver.
Also, for the actual software for the camera, if you need that, you might email or call canon and ask for a replacement copy of it. I can't guarantee you will get it, but it never hurts to ask.
Good luck and let me know if you need my help.