I had this same problem yesterday and is the whole reason I found and came to this site...Bummer that the OP is from 2005 with no other details!
I was in the midst of designing my form - big one with no data connections - and a several day project. Several hours in, I walked away for "just a sec" - which turned into several hours. I had not saved - but had not done anything else either. I returned, did a few more things to my form, ran a preview, fixed a few more things, everything was going just fine. Then, noticed that text was "intermittently" blanking out when scrolling. In the task pane (showing my Data Sources) - all text was blank, but the icons were still there. If I right clicked over a control in the form, the menu was blank. I was freaking out a bit, clicked save - but never got the "Publish" or "Overwrite" buttons, but did get an hour glass, so stupidly assumed I was saving...I closed my form....Then re-opened just to check - ALL changes made yesterday (4 hours worth of work) - GONE.
I'd love to know if there's some secret backdoor way to locate a temp file - or something, anywhere on my computer where I can restore, rather than having to re-create everything I did yesterday.
I'm running Windows XP SP2, and InfoPath 2003. I had two InfoPath forms open in design mode on two monitors - no other apps were running. (Upgrading to anything else is not currently an option.)
Thanks in advance for any insight...