Need help hooking up my canon MP 240 tp my pc.My pc detectsthe printer then says no printer detected.

You need to install your printer first.

If you already have installed your printer, do this:

disconnect printer from computer
cancel documents in queue
if using a straight USB connection, delete all instances of printer. else remove duplicate printer icons.
reboot & reconnect printer (swap cables if not detected)

If you don't have installed your printer do this:

Get your printer software from: www.canon.com

USB printers (Windows 98, Me, 2000, and XP only)

1. Make sure that the USB cable is unplugged from your computer and your printer. USB devices work differently from older devices and usually need to have the drivers installed before you connect the device.
   
   
2. If you have an installation disk, insert it into the drive. If there is an installer provided, it should run or be executed here. Follow its instructions, and it should take care of installing your printer in a few moments.
   
   
3. If you don't have an installation program, plug the USB cable into your computer and your printer. This should trigger the Add New Hardware Wizard.
   
   
4. Click Next, and then select Search for the best driver for your device. Click Next.
   
   
5. Uncheck all options except Specify a Location. Click Browse. Browse to the disk, CD, or directory where your printer drivers are located. Click OK, and then click Next twice. Note: You can download some drivers from the web. Consult the web site of your printer's manufacturer, or see Where can I find driver updates for my Windows computer?
   
6. When all the files are copied, click Finish.
   
   
7. Turn on your printer. Windows should detect the printer's presence and finish the installation. If the option to print a test page is offered, do so. This will confirm the installation. Click Finish.