Controllers are used for attaching Hard Drives, Floppy drives, Com Ports, Printer Ports, Sound Cards, Video Cards and Scanners.
Each one serves there own purpose in completing the system. The HDD,FDC,CP and Printer Port are usually combined into one card .Check the doc's that came with it for proper set up.
If problems arise check the resources and make sure there is no conflicts with other cards. If you have a modem installed usually you will have to disable the com 2 port or change it to com 4.
Standard practice is for the mouse to be on com1 with IRQ4, and for a modem to be on com 2 with IRQ3. If you have problems with the HD or floppy drives the first thing to check is the cables, these have very small wires theat break very easy.
Another thing to check is, remove the card from the slot and see if the contacts on the bottom edge are tarnished, if they are, take an eraser and wipe them till they are clean and shiny, then reinstall the card.
If you are having com port problems make sure the cables are attached to the card properly, pin 1 on the cable is the red trace which always goes to the pin1 designate on the card, this is also true for the drive cables.
Make sure the cables are on the drives properly, pin1 to pin1, check the doc's for the drives to make sure, most drives have a small number on each end of the pin strip to say which is which. Some contollers come with a joystick port, if you have a sound card installed with one you will have to disable one either on the controller or the sound card for proper responce and use from the joystick.
If you are having mouse problems try a diffrent mouse, the ball in them gets worn and won't make proper contact with the surface to rotate the ball, you can buy replacements. Somtimes if when you rmove the ball you will see two plastic rods running acoss the openning, if these are dirty or built up with fibers they can be cleaned or scraped gently with a knife to remove the build up.
Some motherboards don't use use controller cards for a lot of the devices, the new ones coming out now have all the various controllers built in except the modem. On these set up is all done either by jumpers or done in the cmos, check the doc's that came with yours for the proper set up.
Some Scanner cards don't use a com port but do require an IRQ, others require both, check the doc's for proper set up.
