If you use your PC every day, you may sometimes come across files in your hard disk that you want to delete, but cannot. This happens, more often than not, when your PC gets infected with a virus, or worm. When this happens, you will often find many files in your hard disk, that you do not remember seeing before. What’s worse, if you try to delete these files, you will often get an error message stating that the files are open or presently running, and cannot be deleted. Good antivirus software is supposed to clean these files, or erase those, but in some cases, even the best antivirus can fail. That’s when it becomes mandatory to remove these files manually. Here’s how you go about doing that:

1. Before you do anything else, make a list of the files that you want to delete, preferably on pen and paper. If you make the list in your PC, you may not always be able to access it.
2. Now boot your PC in safe mode. This would prevent all but the most essential services from loading. Many infected files (or files created by viruses and worms in the first place) will not have a chance of starting up when you do this. In order to boot into safe mode in Windows® XP/ Windows® Vista, press F8 during booting procedure, just after the initial memory check up is over.
3. Alternatively, you can start up Windows® configuration tool by clicking on Start button, then Run, then typing “MSCONFIG” in the box named “Open” and pressing Enter key. Then select the tab named BOOT.INI in Windows® XP, or BOOT in Windows® Vista. Then simply check the box named /SAFEBOOT, and reboot your PC. Now your PC will always boot up in safe mode. Do not forget to turn this off once you are done.
4. Now start deleting the files one by one. If you fail to delete any file, skip that one for the time being and move on to the next file in your “hit list”. If you delete any file located in the System32 folder inside your Windows folder, make sure you check the dllcache folder (within System32 folder itself) to make sure that there isn’t a copy in there. If you find another copy, then delete it first and select No when Windows® asks you whether to restore the file on the next startup. Now delete the file from System32 as well.

This process may not work for all files that you wish to delete. You can download some good third party utilities, such as, Killbox, Hijack This™, and Unlocker to help you in deleting the files.