Tomo-L,
You mentioned this in your original post but, for the record, can you check the
Processes tab of the Windows
Task Manager one more time in the following manner:
1 - reboot your computer,
2 - open the Windows
Task Manager by your favorite method,
3 - go to the
Processes tab and
then try starting iTunes,
4 - can you now tell us if
iTunes.exe appears on the
Processes list. If so, does it remain in the list or discontinue after a brief period of time?
In the interests of saving some time,
if iTunes.exe appears and remains in the Processes list, let's try deleting the iTunes configuration file as described in
this article in the Apple Knowledge Base.
If
iTunes.exe discontinues after a brief period of time or doesn't appear at all, post back and we can take things from there.