Found it! Windows 2000 source code

/* Source Code Windows 2000 */

#include "win31.h"
#include "win95.h"
#include "win98.h"
#include "workst~1.h"
#include "evenmore.h"
#include "oldstuff.h"
#include "billrulz.h"
#include "monopoly.h"
#include "backdoor.h"
#define INSTALL = HARD

char make_prog_look_big(16000000);
void main()
{
while(!CRASHED)
{
display_copyright_message();
display_bill_rules_message();
do_nothing_loop();

if (first_time_installation)
{
make_100_megabyte_swapfile();
do_nothing_loop();
totally_screw_up_HPFS_file_system();
search_and_destroy_the_rest_of-OS2();
make_futile_attempt_to_damage_Linux();
disable_Netscape();
disable_RealPlayer();
disable_Lotus_Products();
hang_system();
} //if
write_something(anything);
display_copyright_message();
do_nothing_loop();
do_some_stuff();

if (still_not_crashed)
{
display_copyright_message();
do_nothing_loop();
basically_run_windows_31();
do_nothing_loop();
} // if
} //while

if (detect_cache())
disable_cache();

if (fast_cpu())
{
set_wait_states(lots);
set_mouse(speed,very_slow);
set_mouse(action,jumpy);
set_mouse(reaction,sometimes);
} //if

/* printf("Welcome to Windows 3.1"); */
/* printf("Welcome to Windows 3.11"); */
/* printf("Welcome to Windows 95"); */
/* printf("Welcome to Windows NT 3.0"); */
/* printf("Welcome to Windows 98"); */
/* printf("Welcome to Windows NT 4.0"); */
printf("Welcome to Windows 2000");

if (system_ok())
crash(to_dos_prompt)
else
system_memory = open("a:\swp0001.swp",O_CREATE);

while(something)
{
sleep(5);
get_user_input();
sleep(5);
act_on_user_input();
sleep(5);
} // while
create_general_protection_fault();

} // main