The fixes range from expired antivirus suites, remnants of Norton, firewalls and settings to an OS damaged by REGISTRY CLEANERS.
Your story is light but it is too possible that you could repeat what kills it today, tomorrow.
I find those that use registry cleaners find it hard to stop using them.
My pc, running 64 bit Vista, is fine until I try to update iTunes (& a couple of other programs). Upon trying to update iTunes I get an error message stating that "The Windows Installer Service cannot be accessed. This can occur if you are running Windows in safe mode, or if the Windows Installer is not correctly installed. Contact your support personnel for assistance." I contacted the pc manufacturer (HP) & was told, after many different attempts, that the only solution is to reinstall the OS! This takes care of the problem for just a short period of time. I reinstall everything, including the updated itunes software & it's fine 'til I have to update again!
My question: if I were to purchase Windows 7 software would that include a new Windows Installer service (that would ultimately solve my problem) or would it just adapt the one already on my machine?
Thanks very much, in advance, for your time and assistance.