Crear un archivo nuevo y llámarlo "Validación.reg", a continuación abrirlo y pegar esto:
-----------------------------------------------------------------
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion]
"CurrentBuild"="1.511.1 () (Obsolete data - do not use)"
"ProductId"="55274-640-1011873-23081"
"DigitalProductId"=hex:a4,00,00,00,03,00,00,00,35,
35,32,37,34,2d,36,34,30,2d,\
31,30,31,31,38,37,33,2d,32,33,30,38,31,00,2e,00,00
,00,41,32,32,2d,30,30,30,\
30,31,00,00,00,00,00,00,00,86,56,4e,4c,21,1b,2b,6a
,a3,78,8e,8f,98,5c,00,00,\
00,00,00,00,dd,da,47,41,cc,6b,06,00,00,00,00,00,00
,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,38,31,30,32,36,00
,00,00,00,00,00,00,b5,16,\
00,00,83,83,1f,38,f8,01,00,00,f5,1c,00,00,00,00,00
,00,00,00,00,00,00,00,00,\
00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00 ,66,e5,70,f3
"LicenseInfo"=hex:33,b7,21,c1,e5,e7,cd,4b,fd,7c,c6
,35,51,fd,52,57,17,86,3e,18,\
d3,f4,8c,8e,35,32,7b,d1,43,8d,61,38,60,a4,ca,55,c9
,9a,35,17,46,7a,4f,91,fc,\
4a,d9,db,64,5c,c4,e2,0f,34,f3,ea
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WPAEvents]
"OOBETimer"=hex:ff,d5,71,d6,8b,6a,8d,6f,d5,33,93,f d
-----------------------------------------------------------------
A continuación guardarlo y hacer doble click en él, reiniciar y fin de los problemas de validación con Microsoft Update.