How to repair AutoCAD installation?

Step 1: Reset AutoCad to System Defaults :

Windows 7 Operating System:

For most versions of AutoCAD 2012 and later (including AutoCAD-based products), the reset utility can be found in the AutoCAD program group located in the Windows Start Menu:

• Start menu > All Programs > Autodesk > AutoCAD 201x > Reset Settings To Default.

The reset utility gives you the option to back-up your settings first. Once the reset is complete, AutoCAD automatically opens and initiates its secondary installer

Windows 8 Operating System:

1. Click the Windows button to access the Start Screen.
2. Right-click the bottom of the screen.
3. Click the down arrow to access all the installed apps.
4. In the AutoCAD section, click “Reset Settings to Default.”

Windows 8.1 Operating System:

1. Click the Windows button to access the Start Screen.
2. Move your cursor down and click the down arrow to access all the installed apps.
3. In the AutoCAD section, click “Reset Settings to Default.”

Windows 10 Operating System:

1. Click the Windows button to access the Start menu.
2. Click ‘All Apps’
3. Click the down arrow v to expand ‘Autodesk’.
4. Scroll down and click on ‘Reset 201x Settings To Default’.

AutoCAD 2011 and older on the Windows 7 and Windows XP Operating Systems:
For AutoCAD 2011 and older and versions that do not have the Reset utility, one must reinitiate the secondary installer (See Below)

If the problem persists, try to repair the installation from the Control Panel 

Reinitiating the secondary installer procedure:

Manually resetting AutoCAD to defaults involves deleting two folders and a registry path. Here are the steps:

1. Exit out of AutoCAD.

2. If available, export your current settings to save them as a back-up. Do this by going to Start > All Programs > Autodesk > AutoCAD 20xx > Migrate Custom Settings > Export AutoCAD 20xx Settings. If there is no export utility, manually save a copy of the folders mentioned below.

3. Delete the following folders:

   For Windows Vista and newer:

   C:\Users\<user>\AppData\Roaming\Autodesk\AutoCAD 20xx
   C:\Users\<user>\AppData\Local\Autodesk\AutoCAD 20xx

   For Windows XP:

   C:\Documents and Settings\<user>\Application Data\Autodesk\AutoCAD 20xx
   C:\Documents and Settings\<user>\Local Settings\Application Data\Autodesk\AutoCAD 20xx

   Note: These paths contain hidden folders. You must turn on “show hidden files” in Folder Options to see them.

4. Press WINDOWS-R on the keyboard to bring up the Run window, enter REGEDIT and click OK.

5. Delete the following registry key (see warning below) (to manually save a backup, right-click > Export):

   HKEY_CURRENT_USER\Software\Autodesk\AutoCAD\Rxx.x\ACAD-xxxx:40x

   This path is unique for each version of AutoCAD. You can see what ‘ACAD-xxxx’ refers to by selecting the path and then looking at the keys on the right pane of the Registry Editor. One of the keys will show the install path to the associated version of AutoCAD. The ’40x’ number signifies the language version of AutoCAD.

6. Launch AutoCAD 20xx to have it rebuild its settings files.

You may be able to import your settings again to restore your AutoCAD settings if your AutoCAD version has an import settings utility. However, after doing this, if the original problem reoccurs, repeat the manual reset process and discard your exported settings.

Note: This process can be done for the newer versions of AutoCAD, even those with a reset utility, for instance, if the reset utility malfunctions or shows errors when run.

AutoCAD for Mac 2014 SP1 and later:

To reset the palettes:

• Click the Window menu and choose Reset Palettes or enter RESETPALETTES on the command line.

To reset the entire program:

• Hold down the Shift key while starting AutoCAD for Mac.
• In AutoCAD for Mac 2015 and newer, you may click the AutoCAD (or AutoCAD LT) menu and choose the option to reset the program.

• For all versions of AutoCAD for Mac, do the following:

1. Click Preferences under the AutoCAD menu.
2. Click the Application tab.
3. Click the button “Reset Application Options.”
4. Click “Reset AutoCAD.”

Go to Autodesk website. Get a Three year free educational license. you get a download link from website. install and use.

also there are some torrent sites.But you need to use VPN for opening them

You can also go through this sites : cad cam blogs