This is tested in Windows XP. It may work on Windows 2000 and earlier, but there's no guarantees. If you're unsure about editing registry files... DON'T DO IT!
Neither I, nor DIC (and it's founders/members) are responsible for any broken computers caused by YOU editing YOUR settings.
Start---->Run--->regedit
Open:
My Computer--->HKEY_CURRENT_CONFIG--->System--->CurrentControlSet--->Control--->VIDEO--->(expand all until
you see 'Monitor')
Locate:
Name Type Data
DefaultSetting.XResolution REG_DWORD 0x00000400 (1024)
DefaultSetting.YResolution REG_DWORD 0x00000300 (768)
Explanation: The data is stored as a hex value. 0x00000400 = 1024(base 10/decimal)
0x00000300 = 768 (base 10/decimal)
To change the default resolution:
1) Alternate-click DefaultSetting.XResolution
2) Click Modify
3) In the window that opens, change the 400 to 320 [which is equal to 800 in base 10]
4) Click ok.
1) Alternate-click DefaultSetting.YResolution
2) Click Modify
3) In the window that opens, change the 300 to 258 [base 10 for 600]
4) Click ok.
Exit Registry Editor and restart your computer.
The default setting should now be 800x600.
Enjoy.