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Cannot find XP.COM and after uninstall, Firefox installs and same thing.

  • 5 fhreagra
  • 1 leis an bhfadhb seo
  • Freagra is déanaí ó AnnMartin

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Firefox (Windows 7 Home) will not open. Get an error "cannot find XP.COM" I did full uninstall. When downloading the installer Explorer and running it, it stalls at the same place, about 2/3 through the green bar. Disabled antivirus to get it to install and I see the new Firefox Window with all of my bookmarks intact. Close this window and tried to open it again. No luck. Get the no XP.COM error again.

I did do the Windows Restart as directed, by the way.

I suspect a virus or malware got in there.

All Replies (5)

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Hi, if you didn't perform all these steps when you uninstalled, please try performing a Clean reinstall. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location.

To do a clean reinstall of Firefox, please follow these steps: Note: You might want to print these steps or view them in another browser.

  1. Download the latest Desktop version of Firefox from (or choose the download for your operating system and language from this page) and save the setup file to your computer.
  2. After the download finishes, close all Firefox windows (or open the Firefox menu New Fx Menu and click the close button Close 29).
  3. Delete the Firefox installation folder, which is located in one of these locations, by default:
    • Windows:
      • C:\Program Files\Mozilla Firefox
      • C:\Program Files (x86)\Mozilla Firefox
    • Mac: Delete Firefox from the Applications folder.
    • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
  4. Now, go ahead and reinstall Firefox:
    1. Double-click the downloaded installation file and go through the steps of the installation wizard.
    2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

If that doesn't help, and since you suspect malware, you can try these free programs to scan for malware, which work with your existing antivirus software:

Note that not all removal programs will detect all malware, so you may need to run several or all of them.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us. Thank you!

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You are missing something in my explanation. I can't do anything in Firefox because'''' I can't open Firefox''''. I use control panel to uninstall Firefox and the Mozilla uninstsller takes over. I dont't know how much cleaner I can do it.

AVG finds and removes the Heim.C. But it appears in another file.

Wondering if the virus also lurks in the bookmarks?

Please help.

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I have run the following malware detection programs: full scans malware bytes, full scan spy bot search and destroy, full scan ad aware, and full computer scan with AVG.

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You don't need to open Firefox to do a clean reinstall as above - in fact FF must be closed.

Download Firefox from using another browser and save the file to somewhere convenient on your PC - such as Downloads.

Now (following the above instructions), delete the Firefox installation folder, which is located in one of these locations, by default. (To find it - Start Menu > Computer, double click C: drive > Program Files.)

C:\Program Files\Mozilla Firefox C:\Program Files (x86)\Mozilla Firefox

Now double click the Firefox file you previously downloaded, to start the installer.

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Same thing. AVG detects malware and prevents stub installation about 3/4 the way through. Disable AVG and the stub installer is able to complete. AVG blocks the threat but then it will appear elsewhere in the users/AnnMartin/...AppData/Temp. Hein.C. Have AVG block it, will appear again somewhere else in that folder.

I get the same Hein.C notifications using the full offline instsller. AVG says it has blocked etc.

In both instances, using the stub installer and the full installer, Firefox will not open because it cannot find xpcom.