Laptop stuck on "Starting Windows" Screen

First, the specs:

• Windows 7 Home Premium 64 bit
• Lenovo G570
• Intel Core i3
• Let me know if you need anything else...

Now for the symptoms:
My computer has recently been having trouble booting from the shutdown state. I am not having trouble "un-hibernating." The problem seems to only arise if I restart completely or shutdown and then turn the laptop back on. The problem began about 2 weeks ago. The screen got stuck on the image of the windows icon after the little swirling dots come together (boot screen animation). After almost 15 minutes, I lost patience and decided that something was wrong and manually powered down by holding down the power button. I then entered startup repair and restored the system to a previous restore state. This seemed to work and I didn't have problems for about a week. I then turned off the computer and left it at home while I traveled for about a week.

Upon my return, I tried to turn on the computer and it got stuck on the "Starting Windows" screen again. I did the same thing: restored to a previous restore point and tried to turn it on again. It got stuck on the same screen again. I tried to run the startup repair again, but the repair said that it could not find any problems. The repair module shut down the computer after that. I left it alone for about 5 minutes and tried to turn it on again. It booted without any problem. Strange, but OK.

I turned off the computer for the night after using it for a while. In the morning, I turned it on again, and it started without a problem. However, about 10AM, the sound got all scratchy (problem with the audio driver?), so I tried to restart the computer to reset the driver. When I did this, I ran into the exact same problem as the previous day: stuck on startup twice, etc and once again successfully started it up on the 3rd try after doing system restore before an update to Windows (failed restores had error 0x8000ffff).



In response, I turned off auto update and have only been putting the computer in hibernate. However, my battery was drained completely yesterday when I forgot to put my computer to sleep and now it will not start regardless of what I try. I tried system restore and got a 0x8000fff error. I have also tried resetting the BIOS (clearing CMOS) to factory defaults. Thinking it could a hardware issue, I ran a disk check, but it didn't find any faulty drives.

Upon talking to some tech support from Lenovo, I removed the battery and unplugged the machine, then held the power button for 30 seconds and plugged it back in. The computer started up. I then shut it down and ran into the same problem. The fix once again worked. However, the next day. The computer once again got stuck on the boot screen but the unplugging trick didn't work. I tried system restore several times with no luck. I tried starting the computer in safe mode, but the startup got stuck on driver CLASSPNP.SYS.

Finally, I backed up my computer and made an image of my drive. I tried doing a repair install of Windows 7. The repair install finished correctly so I thought the problem was solved. No such luck, as my computer failed to start after I shut it down...

I am wondering what this problem could be a function of? Is there a way to address it or do I need a new machine?

Thanks.