did you try this exact procedure?
left click start in the lower left hand of the screen
left click run
type regedit
left click OK
Now the registry editor will come up
double left click on HKEY_LOCAL_MACHINE
double left click on SYSTEM
double left click on CurrentControlSet
double left click on Control
double left click on Class
double left click on {4D36E965-E325-11CE-BFC1-08002BE10318}
look on the right side of the window for upper filters
right click on upper filters
left click delete
windows will then ask you to confirm deletion
click yes
look on the right side of the window for lower filters
if you do not see lower filters, you may be out of luck on this one.
right click on lower filters
left click on delete
windows will then ask to confirm deletion
click yes
Close all the windows that are open
restart the computer
If that did not work try this:
Restore does not erase your personal files and is reversible.
click start
click all programs
click accessories
click system tools
click system restore
check the box that says restore my computer to an earlier time, click next
select a bold date on the calendar, a date before the problem started, click next
follow through with the restore directions
restart the computer after it finishes
if the system restore does not work, select an even earlier bold date on the calendar and repeat the procedure
try this with at least four earlier dates before giving up and trying something else
If that did not work, and there has been no other avenue, you can try a repair install using the XP installation disk. back up all your files before doing a repair install. normally, repair does not erase the personal files, but just in case make sure your personal stuff is backed up.
Look at Tom's XP forum, fifth post from the top, for the directions.
When all else fails, a repair install usually does the trick.