How about we approach this from a different angel. Would please look in the Event Viewer and post the error codes that are showing at the time that you are getting these pop-ups.
Start> right click on My Computer> Manage> Event Viewer. Be sure that you are looking at the System error records. The error will appear in the left margin, they look like a red dot with a white X inside. At the top of the columns there are titles for each, the Event column is the one that you want. When you find an error follow across to the Event column and right click on the number, choose Properties in the drop down menu, another page will open with a description of the error. Please post the error codes (the number showing in the Event column) and the descriptions.
Another thing to try is to use the Pause/Break key. When you start your computer put you finger on the Pause/Break key (it should be the last key in the top row if this is a normal keyboard) as soon as you see the message press the key and it should hold it so that you can read it. Please post what that message is exactly.
Edited by dc3, 24 March 2008 - 10:27 AM.