Keyboard stops responding after a powersave on...

Question

Hi!On my laptop ACER ASPIRE 5715Z the keyboard stops working after waking-up after entering the powersave "sleep" state.I have to reboot the system and then the keyboard starts working again.I tried to find some hints on internet and I asked the call center here in Italy but I did not find anything useful.Operating system is Windows Vista with all the hotfix and service pack 1 updated online using "Windows Update".Can anybody help with any suggestions? Thanks in advance!