Unable to set printer as Default

d) In the right column, you will find key -- Device, change the value to your Printer name.
e) It is of the format for example: "HP LaserJet 3250 PCL6,winspool,Ne03:".

f)  Right click on the value and click on Rename, change it to your printer name
    (winspool,Ne03: will remain as it is).

   IF this doesn't solve the problem next step is..

SECOND SOLUTION

Again Navigate the registry key

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows\load

1. Start regedit as Administrator
2. look for the previous key on HKEY_USERS (if you use HKEY_CURRENT_USER you will be modifying the administrator key),
   each user it's show with his SID. For see the user SID you could run in a command line the command "wmic user account get name,sid"
3. Do a Right click on the Windows key and select Permissions.
4. Press Advanced button.
5. Remove all the permissions.
6. Click the inherit ... check box.
7. Click OK.


THIRD SOLUTION


1.Open Regedit as an admin user

i)  Click the round Start button
ii) Type Regedit into the Search box and open it when it appears
   
2.Connect to the remote computer

i) Click File > Connect Network Registry
ii) Enter the computer name and click OK
   
3.Navigate to the correct Registry key

Expand the remote computer's Registry at the following node:

HKU > {User's SID} > Software > Microsoft > Windows NT > Current Version > Windows

Note: You can determine the correct SID using PsGetSid from Sysinternals.
   
4.Reset the permissions on the Windows key

i)   Right-click on the Windows key
ii)  Click Permissions
iii) Click Advanced
iv)  Tick Include inheritable permissions from this object's parent
v)   Press OK
   
Hope it will solve your problem as it solve mine..
Thanks You