I recently installed Windows 7 Ultimate x64 on my workstation as a clean install (I had been using RC1). After installing a number of programs I noticed I was getting installation issues. When I went to check the device manager, I get the "class not registered" error, which seems to be with every mmc.exe, since I cannot open mmc.exe from the run line or cmd prompt.I suppose I could reinstall Windows 7, but that seems tiresome. Is there any way to re-register MMC.exe? I looked around and found one solution for XP, but that is probably not going to work in x64.Thanks for any help.Tom

Hi Tom, Does the issue occur when going to Start, type mmc.exe in the Search box and then press Enter? If so, please try check the system files by the steps below: 1. Insert the Windows 7 installation DVD into the DVD-ROM; Click Exit if the auto-menu pops up. 2. Open an elevated command prompt. To do this, click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow. 3. At the command prompt, type the following command, and then press ENTER: sfc /scannow Please see if the issue can be resolved. For more information, please refer to this knowledge base (KB) article. However, if the issue persists, please perform In-Place Upgrade of Windows 7. Regarding In-place Upgrade, it is a tool to repair the system. Through the special upgrade process, we will be able to repair the system. The In-place Upgrade will not affect settings like photos, movies, documents, etc. that are saved on the computer. However, it is recommended to first backup your important information and files to other partitions or other disks. We can have a try to see if the issue works. Turn off Windows features before performing an In-place Upgrade ========================================= 1. Click Start, and click Control Panel. 2. Click Classic View on the left pane, and double click Program and Features. 3. Click "Turn Windows features on or off on the left" pane. 4. In the Windows Features dialog box, uncheck all of the check boxes, and then click OK. If you are prompted for an administrator password or confirmation, type the password or provide confirmation. Now, let's perform the following steps to repair the corrupted files: In-place Upgrade =========== Though this operation will not remove or modify the installed programs and files, I still suggest that we backup the important files before doing this. In addition, we may have to reinstall the device drivers after this operation. Thank you for your understanding. If the Windows 7 DVD is not available, please just run setup.exe file in the Windows 7 installation package to perform the following steps. 1. Insert the Windows 7 DVD in the computer's DVD drive. 2. Click Start and choose Computer. 3. Please find the "setup.exe" file in the DVD-ROM and double click it. 4. Click Install now. 5. When we are prompted to input the product key, please click Next without inputting any key. The setup wizard will prompt and ask if you agree to install Windows 7 without the key. Please choose to confirm. 6. When you reach the "Which type of installation do you want" screen, click Upgrade to upgrade the system files of Windows 7. Note: While performing the In-place Upgrade, the system will restart automatically (several times) to merge the files and programs. Please leave the computer alone and do not configure it until In-place Upgrade is completed. The system will start Windows 7 once it is upgraded. When the In-place Upgrade finishes please check the original issue again. Regards, Linda

Sorry, but this is no help at all. 1) I cannot do an In-Place Install 2) My SFC will nto run at all. and my MMC isgiving me "class not registered. Before I can find out why I can't to SFC or in-place install, I got to get this fixed. I tried "regsvr32 mmcndmgr.dll" but MMC is still not regged. What else? This is the problem you guys answer these questions with the assumption that all the little POS microsoft fixes actually work, you cannot answer with those assumptions, because, sometimes the standard fixes absolutely WILL not work. And wiping and reinstalling is just not an option. I've klept my Windows 2000, XP and now 7 installations perfectly in tune, mostly by not using the standard fixes. This is a new problem, the standard fixes aint working, so what else is there?