I had numerous problems with this laptop (this one being the major one: http://en.community.dell.com/support-forums/laptop/f/3518/t/19601127) which make it pretty much unusable. While trying to somehow solve my problems, I desperately installed the "Dell Update Application". It did not suggest me to update the touchscreen which was the source of my problems, but to update BIOS. This was a huge mistake, because I lost the entire functionality of the sleep mode button. It was pretty much unfunctional untill then, but it still was the only button that could wake up laptop from sleep.
From now on, it is impossible to make the laptop go to sleep with a button press and when it does go to sleep automatically, I cannot wake it up. I can only hold the sleep/power button, lose all my data by making a hard reboot.
After the BIOS update, Windows won’t recognise the sleep/power button at all under "Power Settings". It won’t make laptop go to sleep, hybernate