Windows Vista installer service cannot be accessed

I am getting two errors and not sure if they are related.

I had 2 working Vista Ultimate partition along with another Ultimate
and home partition . Something happened to Boot MBR and I was asked to
repair.

When repair was done one of the Ultimate partition has following 2
problems (Other 2 partitions are ok)

1. The profiles are not saved. I change something and upon reboot
they don't get saved. There is a message also stating to that effect
(comes up in right corner bottom popup). I created a new user and the
new user has same problem as well

2. When I try to launch Windows post installed applications such as
Office or Visual Studio or SQL Server (not OS programs like Control
Panelor games etc or non Windows applications such as Adobe reader or
CanonScan or Yahoo Messenger etc .......they come up fine) ......I
get a stupid error
" The Windows Installer Service could not be accessed.This can
occur if windows installer is not correctly installed.Contact your
support personnel for assistance " .
All of these used to work before. I went and looked at the Windows
Installed Service and it said was started Manually. i even set it to
Auto start but no help

Of course I can reinstall the whole damn OS all over but the point is
I should not have to.

Is there a fix for these two isssues.........are they related ?

Thanks