Add Remove Programs appears blank
I also had this problem where the Add Remove Programs (ARP) form does not seem to populate. I tried a microsoft support article that was cited in several forums (this problem seems quite common), see kb266668, but as far as I could see the necessary registry entries were there. I also ran appwiz.cpl a few times with inconsistent results.
Before I noticed this problem I had also started to experience slow shutdowns or non shutdowns. By process of elimination I considered that a trial version of Macafee antivirus/ security centre may be the culprit. It expired several days ago and was now prompting me on each startup to visit the registration centre (hoping I would buy!).
Since ARP was still blank, I used a Registry utility - Regseeker - to uninstall the two macafee programs. When I pressed restart at FINISH of uninstall, surprisingly the computer (XP Pro) shutdown and restarted normally. So I checked the Add Remove Programs, and it now worked. I did another restart - again smooth - and again Add remove programs worked OK.
So I suggest you should check the startup programs to solve this problem. In hindsight, it may also be true that in at least some instances the population of the ARP may have just been taking a very, very long time (because of the offending program), so some users may just think it was not being populated. However, I have to say that as well as a blank form, I also had several instances where the applet didn't even appear to want to start at all.