Check for Thunderbird update.

Try to Run the thunderbird in Safemode

What is your anti-virus s/w?

-hi, i'm dont have a antivirus program at my pc. -yesterday thunderbird work without problems. but in the middle of the day it freeze and not respond to any request. When i'm turn off it and run again thunderbird work "exelent" about 5-6 seconds and freeze again. -I'm try work in safe mode - doesn't help

Start *Windows* in safe mode with networking enabled.

- Win8 http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode

- Win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode

- XP http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx

Still in Windows safe mode, start Thunderbird in safe mode.

- https://support.mozilla.org/en-US/kb/safe-mode

Does the problem go away?

I'm did all You written, but problem didn't go away to my regret.

I'm installed in my PC "Eudora OSE" same problem

Are you certain you did start Windows in safe mode?

Are you certain you did start Windows in safe mode? 100%

The file with inbox letter was about 2.5Gb, I'm deleted it, but it not help.

I'm beginning to think your problem isn't related to Thunderbird at all. I'd suggest you thoroughly check your computer's hardware, and run a scan for malware as well.