Yesterday, I installed Foxit Reader, then decided I didn't like it. When I attempted to re-install, I received the error message that "the windows installer service could not be accessed." It was listed as running in the services applet of administrator tools, but would not work. While then exploring the system, I found other things that wouldn't work--for example, audio, which is what put me on to the same problem last May--and others. I got many "class not registered" errors. SFC won't run. When booting to the CD and running SFC, I got the old message about a pending repair, although I can find no trace of one. Ran malware scanners, of course, and the system came clean. Clean boot was not useful. The most significant thing I have found, which is probably at the root of this, is that in task manager, there are no instances of svchost running, unlike the usual ten or fifteen that normally run. I had this problem in May, and ended up doing a complete re-install of Windows 7 Home Premium. I would like to avoid going through that again. It's difficult with visual impairment. There is one potential similarity to now and the situaton in May, other than the symptoms described above. In May, I had tried installing a new nvidia card, which Windows wouldn't recognize, so I took it out and when I booted back to Windows, the above symptoms appeared. Yesterday, I saw in event viewer a dcom error, which traces back to the nvidia updatus "user." Thoughts?