Adding applications to your computer is a vital part of using the functions of the device. Since computers were specially made to cater to the different needs of consumers, they must be adaptable to different circumstances. The need for versatility includes a computer's ability to accommodate programs that will increase its utility to users. Yet, there are moments when some problems can be encountered during installations. Computers that run on Windows XP can encounter problems occasionally. Sometimes, hiring a technician to solve these problems or calling for customer support may not be the ideal course of action. To prepare for these occasional problems, it is important to know how to fix windows installers. When installing new programs on Windows for instance, you can encounter an error message that notifies you that the Windows Installer Service could not be gained access you can receive this error message if you are running on safe mode. This can also be encountered if the installer is not installed properly. This can also be caused by an installer service that is damaged or unregistered. You can resolve this problem without hassles if you know how to fix Windows installers. If you do, not then you can be guided by the following steps. First, as an administrator, log on to your computer. Next, click start and choose run. On the box that pops out, type cmd on the Open box and click ok. After that, type msiexec.exe /unregister at the command prompt. Press the enter button and type msiexec /regserver before pressing enter again.  After this step, you should verify that the system is in full control of gaining access permissions in the HKEY_CLASSES_ROOT. The Windows registry must be modified correctly or else you will have several problems with your system. It would also be wise to have a backup of the registry before it is modified so that old settings can be restored if problems occur during the modification process. After doing all those steps, restart the computer and see if changes had been effected. If the problem remains, you should repair Windows XP. It would also be wise to engage the help of an individual who is well-versed in resolving these problems.