I have a Lenovo AIO computer running Win7/SP1/64 purchased in February of 2014. It runs perfectly well except that when I put it in sleep mode, at some point it shuts down improperly. This just started about a week ago. Other than that, it runs fine. I can't think of anything that changed to bring this problem on. I opened it up to clean out any dust to make sure it wasn't overheating but that didn't help. I checked that drivers are up to date. I am using Kaspersky antivirus and ran a full check that didn't show any malware. I don't know what else to do and need help with this frustrating problem. Thanks.