download reshacker and open the following resource:
%windir%\system32\msgina.dll
 
now scroll down to the dialogs. to the right are the source for the scripts that determine what that window and other dialogs look like. the position and size of each dialog are in the first line.
 
here's an example script from my horked msgina:
[tt]1500 DIALOGEX 6, 18, 274, 175
STYLE DS_FIXEDSYS | DS_MODALFRAME | WS_POPUP | WS_VISIBLE | WS_CAPTION
CAPTION "Log On to Windows"
LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
FONT 8, "MS Shell Dlg", FW_DONTCARE, FALSE, 0
{
CONTROL "handle:", 1506, STATIC, SS_LEFT | WS_CHILD | WS_VISIBLE | WS_GROUP, 6, 83, 43, 8
CONTROL "", 1502, EDIT, ES_LEFT | ES_AUTOHSCROLL | WS_CHILD | WS_VISIBLE | WS_BORDER | WS_TABSTOP, 56, 81, 162, 12
CONTROL "pass:", 1507, STATIC, SS_LEFT | WS_CHILD | WS_VISIBLE | WS_GROUP, 6, 100, 43, 8
CONTROL "", 1503, EDIT, ES_LEFT | ES_PASSWORD | ES_AUTOHSCROLL | WS_CHILD | WS_VISIBLE | WS_BORDER | WS_TABSTOP, 56, 98, 162, 12
CONTROL "domain:", 1508, STATIC, SS_LEFT | WS_CHILD | WS_VISIBLE | WS_GROUP, 6, 117, 43, 8
CONTROL "", 1504, COMBOBOX, CBS_DROPDOWNLIST | CBS_SORT | WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_TABSTOP, 56, 115, 162, 144
CONTROL "crawl", 1505, BUTTON, BS_AUTOCHECKBOX | WS_CHILD | WS_VISIBLE | WS_GROUP | WS_TABSTOP, 56, 134, 162, 10
CONTROL "", 2406, STATIC, SS_ICON | WS_CHILD | WS_VISIBLE, 6, 148, 20, 20
CONTROL "go", 1, BUTTON, BS_DEFPUSHBUTTON | WS_CHILD | WS_VISIBLE | WS_TABSTOP, 55, 154, 50, 14
CONTROL "nevermind", 2, BUTTON, BS_PUSHBUTTON | WS_CHILD | WS_VISIBLE | WS_TABSTOP, 109, 154, 50, 14
CONTROL "poweroff", 1501, BUTTON, BS_PUSHBUTTON | WS_CHILD | WS_VISIBLE | WS_TABSTOP, 163, 154, 50, 14
CONTROL "opts", 1514, BUTTON, BS_PUSHBUTTON | WS_CHILD | WS_VISIBLE | WS_TABSTOP, 217, 154, 50, 14
CONTROL "Optional Legal Announcement", 2400, STATIC, SS_LEFT | WS_CHILD | WS_VISIBLE | WS_GROUP, 6, 47, 261, 25
CONTROL "This computer is in use and has been locked.", 1852, STATIC, SS_LEFT | WS_CHILD | WS_VISIBLE | WS_GROUP, 48, 7, 219, 8
CONTROL "Unable to determine User name information.", 1952, STATIC, SS_LEFT | WS_CHILD | WS_VISIBLE | WS_GROUP, 48, 21, 219, 19
CONTROL "", 2404, STATIC, SS_ICON | WS_CHILD | WS_VISIBLE, 13, 7, 20, 20
CONTROL "Unlock Computer", 2421, BUTTON, BS_GROUPBOX | WS_CHILD | WS_VISIBLE, 0, 0, 273, 44
}
[/tt]
 
so, the position of this dialog is 6,18 [x,y].
i think.
i could be completely wrong.
i've only horked the strings and bitmaps, not the definitive ints.
 
if that doesn't work for you, play around with the other ints.
note: to actually view what your changes actually do, you have to run a batch similar to the following.
[tt]cd %windir%\system32\
del msgina.old
ren msgina.dll msgina.old
copy C:\horks\msgina\msgina.dll .\
exit
[/tt]
if you have file-protection enabled, it will ask you if you're sure you want to change a system critical file. click cancel, then yes.
and then REBOOT!
 
of course i can explain what that script does if you don't read batch.

Thanks. I'll give it a try. It's the only suggestion I have gotten so far

actually, msgina is sort of protected.
xp whines when you replace it, but you only have to reassure it that you probably know what you're doing by clicking 2 buttons.