Itunes 7.0.2 Won't Open after install - Got it working (Windows XP SP2)

Question

The Symptom
I spent the whole day yesterday trying to fix this problem. Could install Itunes 7.0.2 and Quicktime ok, but like others on this forum, once installed it flashed up the license screen for a couple of seconds and then nothing!! Very frústrating. This was on my father-in-laws PC and the same install had worked fine on my PC at home.
At the sametime, I had been trying to install Yahoo Messenger 8.x, this too was behaving oddly, in that it installed ok, but did not produce any short cuts or program executables.. so you couldn't run it... and yet, you could install v7.5 of Messenger ok, as you could with Itunes 6.5 and both would ran perfectly well. Got the old versions from www.oldapps.com by the way.
What I tried first, but failed for me.
I tried other suggestions on this forum as well as from other places:
1) Turning off my virus checker and firewall, I was using F-Secure. I didn't believe it was this as I had used the same software on my PC at home and the install was ok there. Still didn't run after the install.
2) Tried uninstalling Itunes and QuickTime several times and rebooting. Still didn't run after the install!
3) Tried installing 6.x of Itunes which worked, and then upgrading to v7 of Itunes, which upgraded ok but of course then wouldn't run!
The solution that did work for me-
On browsing the net for a few hours, which is really what you want to do on New Years eve!?!? I happened to skim read a short piece by someone who had mentioned that their installation of Yahoo Messenger 8.x had failed due to their installation of Internet Explorer v6.x - their IE worked ok, but some install errors for Messenger had seemed to point to it anyway - read that here: http://www.winehq.org/pipermail/wine-bugs/2006-August/036969.html
So, with this in mind, I decided to upgrade the version of I.E. to v 7, as my father-in-law was running v6.x.
So:
1) I uninstalled Itunes and Quicktime using Add/Remove programs, nothing else.
2) (You may not get this issue as I did whilst trying to install IE7 so you maybe able to skip this step)
When trying to install IE7, it came up with the error "Setup could not verify the integrity of the file update.inf. Make sure the Crytopgraphic service is running on this computer", so I had to follow Methods 1-5 in this MS Article in order just to install IE7: http://support.microsoft.com/kb/822798/en-us once those methods had been followed IE7 installed a-ok.
My Father-in-laws machine is a little knackered so you may not have any issues in installing IE7, so I suspect you'll be able to Step 2.
3. Installed IE7 (http://www.microsoft.com/downloads/details.aspx?FamilyId=9AE91EBE-3385-447C-8A30 -081805B2F90B&displaylang=en)
4. Reinstalled Yahoo Messenger 8.0 and Itunes 7.0.2 and both ran up without an issue just before midnight so I was able to go off and enjoy new year with some booze and fireworks
Conclusion
So, my conclusion, and i'm no expert, is that both Yahoo Messenger 8.x and Itunes 7.0.2 rely on Internet Explorer, which I think is a given!.. If something in IE isn't to it's liking it'll fail to run, i.e. a registry entry not quite right - or maybe some port settings, I don't know.
Of course it may have also been the cryptography service error that I resolved in step 2 above.
My advice, would be to either remove Itunes/Quicktime as in Step 1 and then upgrade to v7 of IE or try reinstalling v6.x of IE before attempting the Itunes install again.
Good luck.
Oh, and seperate to the above issue, if anyone received a vbscript error when trying to install Itunes, I had to enter the following command at an MSdos command prompt:
regsvr32 vbscript.dll
and then kicked off the install again.
Hope something in the above helps,
Marcus

Answer 1

If re-starting doesn't help, it could be iTunesHelper that prevents installing.
Locate it in System Preferences>Accounts>Login Items.
Select the item and remove it by clicking on the minus sign.
Log out and in again and try installing iTunes again.
M