If it worked the first time, it should work now if you reinstall it from the original installer. A newer version most likely works after install. Unless, of course, all your cleaning the registry and deleting folders deleted something essential from Windows.
If you prefer an older version, why not install that again from the installer you put on your backup?
Windows XP, SP3. I've been using MSN Messenger since, well, since it was called MSN Messenger. It just worked. For some time now it's been Windows Live Essentials, which just sucks to a degree that is staggering when compared to any other program.
First of all, I have 2 e-mail accounts, it's funny how I couldn't add contacts on one because "this Windows Live service isn't available right now", but I logged out, logged in the other account and voila - added.
So I decided to update my Windows Live Essentials anyway. I use IObit uninstaller, which deletes every leftover files and registry keys. The built-in uninstaller apparently had a seizure and didn't uninstall half of it. Then I deleted the million leftovers. Of course when all this was done there were still lots of broken shortcuts and WL folders around. I used a program called ZapMessenger - the ONLY program that has worked accordingly so far - and it deleted everything but some folders in Common Files.
I tried re-installing WLE just with Messenger, it installs, but really badly. First of all in C:\Program Files\Windows Live\ there's only the Messenger folder, no Installer, nothing. I had to download wlarp.exe from some shady filesharing website, because apparently Microsoft relies on 3rd party to remove its crappy programs. Not only do their programs suck, they don't care to make removal tools available.
So the re-installed Live Messenger won't work, it gives me the 80040154 error meaning I had to get some program called msxml3.msi. Didn't work. Most people with this error say some other program called Contacts-ship-neutral.cab which when I open and run says I already have a newer Contact Platform.
I'm exhausted. I'm sick of Microsoft, sick of the crappy suite that is WLE, sick of searching for error codes. I didn't mark this as a rant because I really need help solving this.