Hello catlover2 and welcome.
Do NOT use Windows system restore, as you could very well lose files that are not covered by system restore.
The error-codes you are seeing and the missing installer service are all connected to the use of registry cleaning, in this case usage of System Mechanic.
You will not get far (without a couple of registry fixes) in Windows updates, since a number of the current updates require the windows installer service.
S M has knocked out a key registry entry that effectively results in windows installer "not showing" {windows update will show cannot access}.
In addition, S M would have also removed the REG association entry in the registry.
These are cure-able.
But I must know your exact Windows version {Windows 7, Vista, or XP ? } Sorry. A re-read of your original post shows VISTA - 64
Do NOT try to re-install the Installer 4.5 package (it's not necessary to jump to that extreme at this time).
The FixIt's will not cure your current situation given that it too depends on the installer service.
Some answers to your questions:
Quote
At the cmd promp I have entered:
net stop wuauserv [enter]
Next I am browsing the C drive for:
Windows\Software Distribution\Download
I have 68 items in that folder going back to Sep. 2010. Is the next step to delete all of these? I assume no adverse affect if these files are deleted?
YES, you may delete all the contents (folders & files) in the \Download folder {just that sub-folder & not the parent folders}. That is recommended to clear the queue of pending/downloaded items)
Quote
Once that is done I understand I should go back to the cmd prompt and enter:
net start wuauserv [enter] ~~~ logoff and reboot
You can hold off on that, but if you have done that, no harm. [The command restarts the windows update service, but we really should leave it alone for the time being. And it will start again anyhow at the next Windows startup.]
As to the Custom scan at Windows Update, hold off until after we have fixed 2 registry entries.
added note
Put back a couple of registry entries
System Mechanic "registry cleaning" has put a double whammy on your system in having removed two registry keys.
The following will put things back in order for the registry {at least for the Installer service}, so that you can then proceed to redo Windows Update.
This are for VISTA systems <<<---
Download this file from Ramesh S
http://www.winhelpon...egfix_vista.zip
Save it to your DESKTOP.
EXtract the contents to your DESKTOP.
go to Start, type in
REGEDIT and press Enter-key
from main menu, select
File
then select IMPORT
navigate the dialog (click on DESKTOP icon on left to select it)
type in
regfix_vista.reg
in the Filename text-box and click Open button.
Once the merge is complete, you will see a confirmation message.
Click OK when done.
Next, get this second registry-fix
Download and SAVE to your system (to the Desktop or a unique folder) the following registry-fix file
http://download.blee...a/msiserver.reg
Do a
RIGHT-Click on
msiserver.reg file and select
MERGE
When it confirms the merge, click OK button.
If prompted by UAC User Account Control, allow to proceed.
IF and only if, the Merge option is not available, then double-click on the file and allow it to merge into the registry.
IF and ".reg" file pops up in REGEDIT, when prompted whether to Merge answer Yes.
When done with the two registry fixes, Exit / close REGEDIT.
then Logoff and Restart Windows fresh.
Post fresh copies of the DDS logs for review.
Edited by Maurice Naggar, 30 May 2012 - 08:55 AM.