Further info, Troubleshooting information,

 Application Basics

   Name: Thunderbird
   Version: 45.3.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; rv:45.0) Gecko/20100101 Thunderbird/45.3.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20160825102941
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account4:
     INCOMING: account4, , (imap) imap.mail.me.com:993, SSL, passwordCleartext
     OUTGOING: , smtp.mail.me.com:587, alwaysSTARTTLS, passwordCleartext, true

   account6:
     INCOMING: account6, , (imap) imap.googlemail.com:993, SSL, passwordCleartext
     OUTGOING: , smtp.googlemail.com:465, SSL, passwordCleartext, true

 Crash Reports
   http://crash-stats.mozilla.com/report/index/bp-c411f46e-2570-48e3-ac2c-89b2c2160206 (6/02/2016)

 Extensions

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 358400
     browser.cache.disk.filesystem_reported: 1
     browser.cache.disk.smart_size_cached_value: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     dom.apps.reset-permissions: true
     extensions.lastAppVersion: 45.3.0
     font.name.monospace.el: Consolas
     font.name.monospace.tr: Consolas
     font.name.monospace.x-baltic: Consolas
     font.name.monospace.x-central-euro: Consolas
     font.name.monospace.x-cyrillic: Consolas
     font.name.monospace.x-unicode: Consolas
     font.name.monospace.x-western: Consolas
     font.name.sans-serif.el: Calibri
     font.name.sans-serif.tr: Calibri
     font.name.sans-serif.x-baltic: Calibri
     font.name.sans-serif.x-central-euro: Calibri
     font.name.sans-serif.x-cyrillic: Calibri
     font.name.sans-serif.x-unicode: Calibri
     font.name.sans-serif.x-western: Times New Roman
     font.name.serif.el: Cambria
     font.name.serif.tr: Cambria
     font.name.serif.x-baltic: Cambria
     font.name.serif.x-central-euro: Cambria
     font.name.serif.x-cyrillic: Cambria
     font.name.serif.x-unicode: Cambria
     font.name.serif.x-western: Cambria
     font.size.fixed.el: 14
     font.size.fixed.tr: 14
     font.size.fixed.x-baltic: 14
     font.size.fixed.x-central-euro: 14
     font.size.fixed.x-cyrillic: 14
     font.size.fixed.x-unicode: 14
     font.size.fixed.x-western: 14
     font.size.variable.el: 17
     font.size.variable.tr: 17
     font.size.variable.x-baltic: 17
     font.size.variable.x-central-euro: 17
     font.size.variable.x-cyrillic: 17
     font.size.variable.x-unicode: 17
     font.size.variable.x-western: 17
     gfx.crash-guard.glcontext.appVersion: 45.3.0
     gfx.crash-guard.glcontext.deviceID: 0x104a
     gfx.crash-guard.glcontext.driverVersion: 10.18.13.5330
     gfx.crash-guard.glcontext.gfx.driver-init.direct3d11-angle: true
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle: true
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-d3d11: false
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-warp: false
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-try-d3d11: true
     gfx.crash-guard.status.glcontext: 2
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: aaa0f574-12e3-4c08-a11c-548e09cd69b
     network.cookie.lifetimePolicy: 2
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1473073194
     places.history.expiration.transient_current_max_pages: 93304
     plugin.importedState: true
     privacy.donottrackheader.enabled: true

 Graphics

     Adapter Description: NVIDIA GeForce GT 610
     Vendor ID: 0x10de
     Device ID: 0x104a
     Adapter RAM: 2048
     Adapter Drivers: nvd3dum,nvwgf2um,nvwgf2um
     Driver Version: 10.18.13.5330
     Driver Date: 6-17-2015
     Direct2D Enabled: false
     DirectWrite Enabled: false (6.2.9200.17568)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: Google Inc. -- ANGLE (NVIDIA GeForce GT 610  Direct3D11 vs_5_0 ps_5_0) -- OpenGL ES 2.0 (ANGLE 2.1.0.316930d51ea9)
     GPU Accelerated Windows: 0

     AzureCanvasBackend: skia
     AzureSkiaAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: cairo

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 0
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.12
     4.12

     NSS
     3.21.1 Basic ECC
     3.21.1 Basic ECC

     NSS Util
     3.21.1
     3.21.1

     NSS SSL
     3.21.1 Basic ECC
     3.21.1 Basic ECC

     NSS S/MIME
     3.21.1 Basic ECC
     3.21.1 Basic ECC

As I have said it is only the "me" account that has a problem. Cheers, Phil.

I have not been able to D/L nor send emails from my "me.com" accounts for the last 4 days

What actually happens when you attempt to get mail? Any error message? Does the iPad use the exact same server settings? What is your anti-virus software?

I get a "login failed" box that says, Login to server imap.mail.me.com failed. There are 3 choices under this, Retry - Enter New Password - Cancel I know the password is correct but tried to re-enter the password but it made no difference. I clicked on cancel & another box labelled "Thunderbird" pops up in the right hand lower corner. The msg is, The server may have gone down or there may be a network problem. This box goes away after about 10 seconds. Hope this helps, Phil.

To diagnose problems with Thunderbird, try one of the following:

• Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
• Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.

Have tried all except restarting win7 in safe mode with networking. From what I can see I cannot use the wireless keyboard until windows starts & activates the wireless transmitter. Starting T/bird with add ons disabled made no difference. I tried restoring my computer to an earlier date, have had a windows update around the same time as this started, but that did not work either. I have not added any new programs in the last couple of months or changed any of my settings or programs, antivirus etc.

Have tried all except restarting win7 in safe mode with networking.

That's the key. So you'll need to find a wired keyboard.

I have now tried everything I can think of but problem is still there. I tried deleting the account and adding a new account in T/Bird but same problem. Despite your suggestion Christ1 I believe T/Bird is the problem but will find a wired keyboard & try what you have suggested, might have to buy a cheap one. If all else fails I will delete T/Bird & reinstall or find another email client. Watch this space.

I still have this problem. I have even tried deleting T/Bird completely and D/Ling a new copy from Mozilla thinking that this may fix whatever is wrong but after reinstalling it the problem is still there. T/Bird will not recognise my email password for me.com account so cannot complete setup. Also even after deleting everything when I reinstalled T/Bird all my address book, saved emails and gmail account details were still there. These should have been deleted along with T/Bird. Where is T/Bird getting this info from? I am thinking of just forgetting T/Bird and going to another email client like opera.

The data is all in your profile. By design the profile remains in place when you re-install, upgrade or downgrade.

If you want a clean start, try with a new profile.

https://support.mozilla.org/en-US/kb/profiles-tb