Original Title: System tools don't seem to be working.Receiving error "MMC.EXE - Parameter is incorrect" when trying to use the device manager.Receiving error "C/Windows.0/System32dfrg.MSC" when trying to defrag.Can anyone help?

Hi Pudd12,· In the error message "C/Windows.0/System32dfrg.MSC" is it Windows.0 or Windows?· Do you see two Windows folder when you open C drive in “My Computer”?· When exactly do you get these error messages?Try the steps below and check if it helps:Step 1:Try the steps suggest by Ramesh Srinivasan MVP in the following link and check if it helps:http://social.answers.microsoft.com/Forums/en-US/xpprograms/thread/230d6237-c536-43bf-b110-cdbdf0a28798Step 2:a. Click Start and click Run.b. Type the following command and press enter:regsvr32 C:\Windows\system32\msxml3.dllc. Click OK and wait until Windows confirms that the dll has been registered successfully.d. Now open Windows Explorer and browse to the following folder:C:\Documents and Settings\username\Application Data\Microsoft\MMCe. Look through the files in this folder and locate the file with the same name as the msc file that appears in the error message.f. Rename the file to mmc.oldg. Check if the issue is resolved.Hope this helps.Thanks and Regards,Santosh Y – Microsoft SupportVisit our Microsoft Answers Feedback Forum and let us know what you think.