Currently, the time I have slept for sleep is 30 minutes. If I leave the computer alone for 30 minutes, the screen turns off, the mouse turns off but the computer doesn't, and it is frozen with no way to revive it and I have to do a hard shutdown. I changed the setting from sleep to hibernate after 30 minutes of inactivity, but exactly the same thing occurs. Sometimes, if I leave the computer much longer, I find that the computer is off, and when I turn it on, the message comes up "your computer shut down unexpectedly" etc but it turns on fine in normal mode.My computer is a HP pavilion a6780a, connected to an ordinary home network with a network printer(if that has anything to do with it I don't know). I was running Windows 7 with no problem for two weeks. Then a software malfunction occurred, and I reinstalled the whole operating system (including the vista home system that came with the computer and then windows 7) and it just hasn't worked ever since. The problem occurs 100% of the time.Any suggestions on what might fix the problem?

Both Vista and Win 7 have a hybrid sleep that needs the power button pushed briefly to wake the computer. Hibernation is still a problem on some power settings. I found that the network card was rousing the computer during hibernation and preventing hibernation. Changing the power management setting for the network card to NOT allow this to wake the computer solved the problem. I also learned that you must uncheck the Allow Hybrid Sleep setting in Power settings, Advanced. I found this tip in this article: http://support.microsoft.com/kb/929658/en-us. Even though it's for Vista, it worked in both vista and win 7. Another thing to change is turning off the hard drive. I set it to Never.Mary