Lately, I have been getting this error. This is quite a pain when it comes to installing some things, like the newest version of iTunes, some games bought through Steam, etc. I also think it may be the reason why some updates aren't installing right away anymore. I also can't access things like Add And Remove programs, and I believe this is it (as another question, is it potentially? If not, then what is?). Because of it, thins like Adobe Flash Player also won't update. Lately, I've been trying to find a way to fix it, but none work. When I try to Google how to reinstall it, I usually get old XP help, or Vista- and I'm not sure that works. This is a problem that's really annoying me, and I will take my laptop to Geek Squad if I can't figure this out. To clarify, this is a Windows 7, Acer, 64 bit. If anyone can help me repair Windows Installer Service for Windows 7, or show me some place were I could reinstall this, I'd be REALLY thankful! I'm not familiar with these forums, so if I submitted it to the wrong place, I apologize. If so, can someone tell me were the correct place to ask this question would be?