BSOD Driver_power_state_failure Every 1-2 Days

I've had a Dell Laptop (l502x) with Windows 7 Premium 64 Bit for almost a year now.It's a great thing, except for one thing: i get about 1 BSOD every 1-2 days.As it happens only once every other day, i almost got used to it, but now it's starting to get on my nerves and I'm wondering what is causing it, as they are totally random.On the Dell support website they told me to try the Windows Debugging Tool, which then showed me it had to do with wwussf64.sys. According to some dubious 'anti-virus' sites on the internet this was linked to some Ericsson software, although i don't have any.Might be interesting to know, when they delivered the laptop in 2011, the backlit keyboard was not working, and they had to replace the keyboard and motherboard twice to get it working.