BIG problem with Windows Installer

My problem began when I started to sporadically receive pop-up messages in the lower right hand corner of the desktop stating “Local Area Network A Network Cable Is Unplugged” which would then freeze my mouse and keyboard. (Windows XP Home Edition) This would happen irregardless of being connected to the Internet or not. So I (foolishly?) did a system restore to a check point around two months prior. That not only didn’t solve that problem, but gave me a new problem. In addition to LAN message/freezing problem, when I reboot I also get a “Windows Installer Preparing to Install” message that comes up and stays up for minutes at a time. More frustrating is that the installer message comes up every time I try to open nearly every program, including IE. Programs will run fine, but I have to wait five minutes for the installer window to go away before I can run anything. (Hitting cancel doesn’t speed things up either).
So I found the “READ & RUN ME FIRST Before Asking for Support” page on Major Geeks and religiously went through all the steps to clean and remove Malware, and so far it appears that my LAN message/freezing problem has been solved (thank you!), but the windows installer problem remains. I can’t undo the system restore, because the READ & RUN ME FIRST process wiped out that history.
Granted my computer (HP pavilion a730n) isn’t exactly in flames, but this is a serious annoyance, and any suggestions would be welcome. I tried to search for a similar problem on the forums, but didn’t see anything.
Thanks

 

Unfortunately running Dial-A-Fix (selected all options and rebooted) didn't fix the problem. I do appreciate the suggestion though!
Could my computer be trying to constantly install a program that isn't there any more?
One thing I also noticed is that the installer window will NOT pop up when I run Microsft Word, but it will for most other programs.