Why do app updates no longer show up for me in iTunes?

Question

Please don't stop reading, because I think my issue is different from similar ones I've found posts about.
For the past week or so, I've been unable to update apps through iTunes. When I click "Check for Updates," it shows "Accessing iTunes Store" at the top of the screen, but after it finishes I never get a dialog box -- neither the dialog box saying there are new updates nor the one saying there are not. Also, I don't get the notification in the left hand column next to "Applications" that normally shows how many app updates are available. The latter point is what seems to distinguish my problem from the other posts I've seen, in which push notification seems to work but updating fails. I can't even see any updates in the first place -- and this occurs even when I can see from using the App Store on my iPhone that I have multiple updates available. And I have a lot of apps.
I should add that this is especially mysterious because it is the only problem I am having with iTunes. I can still download NEW apps from the iTunes App Store, sync my iPhone, download podcasts, etc. I can also update Apps on my iPhone itself. My internet service is working fine. This problem began with the previous version of iTunes and has continued in iTunes 8.1.
One final confession. A few weeks ago, I went through my Apps folder and deleted the non-current versions of all of my apps, hoping to save space on my old computer's hard drive. I don't think this is the cause of the problem, because app updating continued to work for a few weeks after that. But I mention it in the interest of full disclosure. But in addition to my main question, I'd be interested in knowing if this is a bad idea for future reference.
I am running iTunes 8.1.0.51 on Windows XP Home edition (SP 3), and I have a first-generation 4GB iPhone.
Can anyone help?
Thanks very much!
Matthew
NYC area

Answer 1

ell, exactly same problem here: could not have been described better. It all started when I noticed that I could no longer update iPhone apps. "Applications" folder under Library showed such updates awaiting downloading: I could not get any further.
AND SUDDENLY, for no reason, the "Application" in iTunes "Library" disappears! No folder visible, no apps listing, no updates mentioned. Wow!
i had contacted Apple's iTunesStoreSupport in regard to the initial incident, and was kindly informed that:
+"Dear Roger,+
+Thank you for contacting iTunes Store Customer Support for assistance. I understand that you are receiving intermittent connection errors using iTunes 8.1.+
+Apple is currently working toward a resolution for the issue you have reported. You will receive an email after the matter has been investigated and further information is available.+
+Thank you very much for your patience, and I am sorry for any delay in enjoyment of your iTunes experience. Finding a solution for you is important to me.+
+Remember, we wish your iTunes experience to be truly enjoyable. Take care, and thank you for being a valued iTunes Store customer. Your business is most appreciated.+
+Best regards"+
I thus figured that in some way "all was in control"... Until the Applications forum disappeared. Apps gone??? Are they stored somewhere on my Mac??
I have just emailed an update incident report to iTunesStoreSupport with screen prints to show abrupt, undesired change.
- Roger T