USB Keyboard and Mouse not working

I have a Dimension C521 with the XP Operating Systems.  The problem is when I boot my pc in normal mode or safe mode my mouse and keyboard do not work any longer.  So what caused this to change.  Well I bought a Belkin USB Flip Controller so I could control two a second C521 with the same mouse, keyboard and Monitor.  The second C521 recognized the device just fine and things worked just dandy.  However, the first C521 did not recognize the device and asked to install a Generic USB Hub.  I said yes and install the Generic USB hub.  This really did not solve the problem.  So I started reading the troubleshooting guide and the guide said to make sure you have USB enabled so I went into the BIOS and sure enough the usb settings were turned on.  In an effort to make sure no on had changed them before I set the BIOS back to the factory settings.  This seemed to cause some problems with the floppy drive being recognized as a real drive, but I went into the BIOS and turned that off so that problem went away.  So I rebooted and still no keyboard or mouse working with the FLIP control.  So I got rid of the flip control and used the keyboard and mouse and monitor directly and eliminated the flip control.  Downloaded some enhanced software off of the Belkin website thinking it would install some drivers for the FLIP control.  I put the software on to a USB Memory stick.  I put the stick into USB in front and the found new hardware window came up.  It asked to install a USB Human Interface device and I said yes.  The USB Key started working and I installed the FLIP software just fine.  So rehooked up the FLIP controller and that still did not work, in fact, now that I have rebooted the keyboard and mouse no longer work at all in safe mode or in normal mode and when I boot up the Found new hardware wizard comes up and asks to install a USB Human Interface device.  Why I have no idea since the only things that are connected to the computer are the keyboard, mouse and monitor.  The found new hardware wizard does seem to recognize a few things in the small bubbles that pop up in the task bar.  It says "Found Dell keyboard" Then "Found USB Human Interface Device", then "Found Dell Mouse" and then it brings up the dialog box to install drivers for the USB Human interface device.  Well I cannot due that because the keyboard or mouse do not work and I am simply stuck.  Bottomline, the keyboard and mouse do not work now with or without the FLIP control  (keyboard does work in the BIOS screen) and I basically cannot due anything.  Anyone have any ideas on what to do?