registry fix?

I have a dell dimension e510 running windows xp and here is my problem -First off the computer has no ps/2 connectors -I start my computer with the mouse and keyboard plugged into the usb ports, it works outside of windows (F2 to get into the bios, F8 to do a safe start, I can move around in them with the keyboard) -I get into windows and the mouse and keyboard don't work at all, I can't navigate anywhere -I unplug the keyboard and mouse and restart and plug them in when windows is loaded it says it loaded the drivers, and since I have an optical mouse I know it's getting power, but it's not working at all. -I've tried every USB port on there and I get nothing -I get power to my flash drive but can't do anything because once again the keyboard and mouse Before all this trouble I was having troubles with my dvd burner and came across a fix for my problems, or so I thought, using regedit, these were the instructions In the Open box, type Regedit, and then click OK. Click the plus sign (+) next to HKEY_LOCAL_MACHINE. Click the plus sign (+) next to SYSTEM. Click the plus sign (+) next to CurrentControlSet. Click the plus sign (+) next to Control. Click the plus sign (+) next to Class. Click {4D36E965-E325-11CE-BFC1-08002BE10318}. On the right hand side of the window, click UpperFilters. Click Edit on the menu bar. Click Delete, and then click OK. On the right-hand side of the window, click LowerFilters. Click Edit on the menu bar. Click Delete, and then click OK. Click File, and then click Exit. Restart the computer normally. To my surprise there were about 15 different "4D36E965-E325-11CE-BFC1-08002BE10318" in there so I went to all the Upper filters and deleted them (I don't remember the names, there were 3 upper and 3 lower) I restarted the computer and now here I am with this delema. once this happened I tried rebooting in safe mode, I tried last known good configuration, and I even had a tuneup utilities backup that I made about a year ago that I decided to try out. None of which helped. I've tried everything in the bios (which is barely tweakable on a dell). I even restored the bios settings to factory default. And still nothing. is there a way to fix the UpperFilter and LowerFilters so that me keyboard will start working again?