iMac not waking up sometimes from sleep

Hi all I have had this iMac for about 6 weeks now and every now and then it won't wake from sleep mode. Reading this on the net it's a huge problem. I have just installed a new HDD and a fresh install of Lion yesterday. After about 8 hours of use it locked in sleep mode. The screen is dark but keyboard and mouse won't work. Caps lock light doesn't work either. Some people report pressing the power button once then a key works but this doesn't work for me. Being new to mac's this is not good (LOL) as I'm about to smash this thing and go back to a PC. Only 3 times in the 6 weeks it has frozen on me with the mouse not moving at all and needs a hard restart. Since reloading Lion yesterday, doing all updates etc I have loaded the minimum apps etc to see if this helps. I'm just worried it's hardware and i'm stuck with a dud. Thanks guys.

Max

Is the iMac new or did you buy it used? If it's new and you've only had it for 6 weeks it should still be in warranty. Make an appointment with your local Apple store and take it on for them to look at.

If it's used, try resetting the SMC as that controls the power features.

chscag said:

Is the iMac new or did you buy it used? If it's new and you've only had it for 6 weeks it should still be in warranty. Make an appointment with your local Apple store and take it on for them to look at.

If it's used, try resetting the SMC as that controls the power features.

Click to expand...

Hi chscag it's second hand. I just looked up what SMC is (lol). I guess I have done this since I installed a new hard drive, loaded Lion then took the iMac back home and plugged it back in. I have also just tried the PRAM. Thanks for the info. I need all the help I can get. Love my iMac, iPad 2, iPhone but atm I feel sick thinking that what I thought I had was bullet proof and is causing me trouble like some of the PC's i've had in the past. Thanks


Max