Canon Powershot SD600 Connectivity/Recognition Problem

Help! I've had a Canon Powershot SD600 for about 6 months, and it has worked absolutley fine on my Dell Inspiron 6000 with Windows XP Home Edition. Today, I tried to connect it and instead of the normal device connect tone, I got three quick tones, and then my computer said it couldn't recognize the camera, and that "there was a problem during installation, and my device might not work properly". I couldn't get it to work, so I called Canon tech support, with no luck. They said there might be a conflict with my Dell printer, but they have been working up until today. I looked under "device manager", and it shows the camera with a yellow exclamation point. I disconnected my printer and re-connected it, and the printer showed the same exclamation point, but then still printed when I tried it. So, I tried uninstalling my Canon software, and re-installing it with no luck. Then I tried doing an upgrade install of Windows XP with no luck. I then tried to download a new driver under the device manager with no luck. Last week, I think I may have got some spyware on my computer recently, as I keep getting a message that my "current security settings do not allow this file to be downloaded" followed sometimes by a pop-up for a search engine or something similar. I also keep getting a "this file needs to close" message for the program "attrib.exe". Not being a computer genius, I deleted "attrib.exe" and realized today when looking for an answer that I may have deleted something important. Could this be related to the problems I am having with my camera? Canon said that I could buy a card reader, but I want to try to get my computer to recognize my camera again. Help please! I am utterly lost and don't want to pay Dell a huge chunk of money for tech support unless I really have to! Any or all advice would be most welcome! Thank you!