I had this problem too. Running 32 bit Vista on a Toshiba Satellite U305 laptop. When you fold the lid it doesn't matter if Firefox is running or not, when you open it and the system wakes up, then Firefox 7.0.1 doesn't work any longer. Firefox either will not load if it wasn't running when the system went to sleep or it will soon hang if it was running. I started having this problem 2 weeks ago and have since then been uninstalling and reinstalling software that recently updated, checking configurations etc of ZoneAlarm, AVG, Acronis, etc. but nothing I did seemed to resolve the problem. Then this morning I was about to rebuild my system and remembered something I did a couple of weeks ago, install iTunes to support a used iPhone I was given. I decided to try removing iTunes before undertaking a rebuild and this fixed the problem. Now that I think about it, I installed iTunes on this laptop when it was new and had to remove it because it slowed it down so much. It looks like they resolved a lot of iTunes performance degradation over the years but iTunes still appears to slow your system down and obviously, now also stops Firefox from working. Whose fault is it, Microsoft, Firefox or iTunes? Good luck having them work it out :-). Removing iTunes resolved my own problem. I can live without iTunes but not without Firefox :-) Note: When the problem occurs, firefox.exe is running in the task manager but you can't kill it. Another problem for the research team. My own research found that MS Vista turns out to be one of the few OS's in the world that doesn't always provide for killing a process. (Lucky me for buying a laptop that has no XP drivers and doesn't warrant the expense of upgrading to 7). Reason for the kill problem? From what I understand, a kill instruction requested of Vista has it asking an application for permission before doing so. Problem is, hung applications rarely reply "sure go ahead". ///// UPDATE://////// After 12 hours and 4 iterations of putting the laptop to sleep and waking it up, the problem has now recurred. So uninstalling iTunes is not the solution (although it seemed to help at first). Sorry if this confused anyone. My plan now it to regress to an older version of Firefox and see if that fixes the problem. However, I probably need a fresh install anyway after 3 years of overcrowding.