|"Nothing in the Event viewer is related to Nero or Acrobat Pro applications"|
If any error event happened at the same time you tried to do something and that didn't work, that event probably IS related to your problem.
e.g. Try doing whatever isn't working in Nero 11, note the time, then looking in the event viewer to see whether an error or warning event happened at the same time or close to the same time.
"i updated manually the Adobe Acrobat Pro X (i downloaded the patch) and NOW
THE 'CHECK FOR UPDATES' OPTION IS WORKING"
" The problem with Nero 11 still exists "
What has the problem with the Welcome screen got to do with it accessing the internet ?
Similar to what I said above....
Was Nero 11 working fine regarding accessing the internet previously ?
, or has that never worked since you last installed it ?
As I said above...
"Do you have more that one burning program installed that did not come with Windows ?"
Such programs often have at least one resident module - a part that runs all the time Windows is running - e.g. Nero and Roxio versions DO have that. If more than one third party burning program has been installed in Windows, if more than one of them has such a resident module, it's likely that those resident modules will CLASH with each other and cause you problems, and one or more of them are likely to NOT work properly.
To avoid that possible problem, you should NOT have more than one third party burning program installed at a time.
If it is the only third party burning program installed, if it hasn't worked properly since you last installed it, this may be the cause of it not working properly...
NOTE that sometimes the resident module(s) of anti-malware programs - a part that runs all the time scanning for suspicious activity - will interfere with the proper installation of third party software, or major Microsoft updates that cannot be installed automatically by Automatic Update, the software will not install properly, and you may get no indication of that at all while installing the software.
To avoid that possibilty, you should always DISABLE the resident module(s) of anti-malware programs, BEFORE you install third party software (software other than most Microsoft Updates, etc., that did not come with Windows ), especially when it's a major or complicated software package.
E.g. if you are using the free or paid version of AVG, you should disable the Resident Shield in AVG's 's settings in Windows (in AVG 2012 that's done under the title AntiVirus). In Norton (Symantec) products, there may be several things you need to disable, or set so they don't load for a specific short amount of time.
If you don't know how to do that, tell us which anti-malware software you are using.
When you are sure the software has installed correctly, re-enable the resident module(s).
How to disable your security applications
By the way, you should also NOT have more than one third party anti-malware program installed at the same time if more than one of them has a resident module.
E.g. the free version of Malwarebytes has no resident module that can cause the problem; the paid version of it does.
AVG free and paid, Avast free and paid, AdAware free and paid, Spybot free and paid, Norton (Symantec) products, McAfee products, Microsoft's Security Essentials all have at least one resident module.
Microsoft's Windows Defender anti-spyware software is built into Vista and Windows 7 - it has a resident module. When you install Microsoft's Security Essentials , and most major anti-malware software that also has an anti-spyware feature, Windows Defender's resident module is usually automatically disabled by the other software, but there are exceptions to that. Windows Defender cannot be un-installed from Vista or Windows 7, but the resident module can be disabled from running in it's own settings.
If you suspect that might be your case, un-install Nero 11, disable your resident module(s), install nero 11 again.
Note that some Windows installations will have problems if you install the InCD feature of Nero. If you never use that feature, or in any case you could try this, choose a Custom installation of Nero or similar and de-select installing InCD.