User without permissions on SharePoint library in a certain computer

Question

I'm really stuck with this problem. Something on our sharepoint (or maybe in the user's computer) is preventing them from using certaing library features:

1. The user cannot see the upload multiple documents option
2. When in the explorer view, the user cannot upload documents, the error is Access Denied.
3. Sometimes the delete option doesn't appear on an element's contextual menu (folder, file).

The user has Full Control permissions over the site/library/elements and When the user logs in from another computer everything works in the expected way.

EDIT: The error is ocurring on Internet Explorer 8. We also did a downgrade to IE7 and the issue continues. The only way we've had to resolve this in the past, has been the operating system reinstalling. The client is using Windows XP and Office 2010.

Answer 1

Its not full answer to your question but it seems like a browser issue for

The user cannot see the upload multiple documents option

It happens to me when I use chrome but it should work fine on Internet Explorer or it will ask you to install some plugin which will solve this particular issue.