When I am turning on the bluetooth this error message appears "The application Settings (process com.android.settings) has stopped unexpectedly. Please try again."

SOURCE: trying to remove win32 trojan and inadvetently

If you have enough hard drive space you may be able to load Windows on a new partition and load windows then download a anti virus protection such Windows Essentials or Avast Home edition ( free) work well and the scan you drive.
Sometime it works sometimes it doesn't depends on the virus.
All else fails is to fully clean the hard drive and start over.
I hope this helps!
You may want to use another PC to get the anti virus downloads and install them.

SOURCE: I can't get into windows

You most likely have a hardware issue. Very possibly memory.
You'll need to troubleshoot that by disconnecting everything in the case but the video, CPU, and memory and see if it starts OK.
Then hook up the hard drive and see if you can boot into Windows. If you can't, unplug one of the memory sticks and try it. Then the other memory stick and try.
If you have a Windows startup (installation disk), boot from that and opt for system repair. You will want to get to the command prompt and run chkdsk.
See my tip here:
http://www.fixya.com/support/r4501608-when_windows_xp_start_primary_fix

Testimonial: "I am not a computer technician so I am unable to do what you suggest. Any idea whee I could get help?"

SOURCE: Hi, My laptop doesn't boot up. I got a blue screen

Thats known as a blue screen of death. you simply have to put in an operating system CD which is bootable (the one which you are currently using win xp vista or whatever) just boot through the cd ignore the first repair option and hit enter when the option for repairs appears for the second time just hit R and follow the options. you won't loose any data.

SOURCE: Dell Inspiron mini - received

reinstall your OS from disc this should cure this problem

SOURCE: Blue screen error STOP: c000021a

It appears that your Windows Registry is corrupted. You can try to use a Registry repair utility like CCleane to fix it. If that doesn't work you will have to reload Windows OS (Operating System). For more info no this error code Google "c000021a".