diff -rupN --no-dereference Python-3.10.9/Include/cpython/fileutils.h Python-3.10.9-new/Include/cpython/fileutils.h
--- Python-3.10.9/Include/cpython/fileutils.h	2022-12-06 19:31:21.000000000 +0100
+++ Python-3.10.9-new/Include/cpython/fileutils.h	2022-12-08 09:37:03.418024952 +0100
@@ -135,9 +135,7 @@ PyAPI_FUNC(wchar_t*) _Py_wrealpath(
     size_t resolved_path_len);
 #endif
 
-#ifndef MS_WINDOWS
 PyAPI_FUNC(int) _Py_isabs(const wchar_t *path);
-#endif
 
 PyAPI_FUNC(int) _Py_abspath(const wchar_t *path, wchar_t **abspath_p);
 
diff -rupN --no-dereference Python-3.10.9/Include/osdefs.h Python-3.10.9-new/Include/osdefs.h
--- Python-3.10.9/Include/osdefs.h	2022-12-06 19:31:21.000000000 +0100
+++ Python-3.10.9-new/Include/osdefs.h	2022-12-08 09:37:03.418024952 +0100
@@ -10,7 +10,6 @@ extern "C" {
 #ifdef MS_WINDOWS
 #define SEP L'\\'
 #define ALTSEP L'/'
-#define MAXPATHLEN 256
 #define DELIM L';'
 #endif
 
diff -rupN --no-dereference Python-3.10.9/Modules/getpath.c Python-3.10.9-new/Modules/getpath.c
--- Python-3.10.9/Modules/getpath.c	2022-12-08 09:36:56.842024805 +0100
+++ Python-3.10.9-new/Modules/getpath.c	2022-12-08 09:37:03.419024952 +0100
@@ -13,6 +13,11 @@
 #  include <mach-o/dyld.h>
 #endif
 
+#ifdef MS_WINDOWS
+#include <windows.h>
+#include <shlwapi.h>
+#endif
+
 /* Search in some common locations for the associated Python libraries.
  *
  * Two directories must be found, the platform independent directory
@@ -148,6 +153,15 @@ typedef struct {
 static const wchar_t delimiter[2] = {DELIM, '\0'};
 static const wchar_t separator[2] = {SEP, '\0'};
 
+static int
+is_sep(wchar_t ch)
+{
+#ifdef _WIN32
+    return ch == SEP || ch == ALTSEP;
+#else
+    return ch == SEP;
+#endif
+}
 
 /* Get file status. Encode the path to the locale encoding. */
 static int
@@ -170,7 +184,7 @@ static void
 reduce(wchar_t *dir)
 {
     size_t i = wcslen(dir);
-    while (i > 0 && dir[i] != SEP) {
+    while (i > 0 && !is_sep(dir[i])) {
         --i;
     }
     dir[i] = '\0';
@@ -242,7 +256,7 @@ joinpath(wchar_t *path, const wchar_t *p
             return PATHLEN_ERR();
         }
 
-        if (n > 0 && path[n-1] != SEP) {
+        if (n > 0 && !is_sep(path[n-1])) {
             path[n++] = SEP;
         }
     }
@@ -334,7 +348,7 @@ copy_absolute(wchar_t *abs_path, const w
             }
             return _PyStatus_OK();
         }
-        if (path[0] == '.' && path[1] == SEP) {
+        if (path[0] == '.' && is_sep(path[1])) {
             path += 2;
         }
         PyStatus status = joinpath(abs_path, path, abs_path_len);
@@ -614,7 +628,11 @@ calculate_set_prefix(PyCalculatePath *ca
         if (prefix == NULL) {
             return _PyStatus_NO_MEMORY();
         }
-
+#ifdef _WIN32
+        wchar_t drive_root[3];
+        memset(drive_root, 0, sizeof(drive_root));
+        wcsncpy(drive_root, prefix, 3);
+#endif
         reduce(prefix);
         reduce(prefix);
         if (prefix[0]) {
@@ -625,7 +643,11 @@ calculate_set_prefix(PyCalculatePath *ca
 
             /* The prefix is the root directory, but reduce() chopped
                off the "/". */
+#ifdef _WIN32
+            pathconfig->prefix = _PyMem_RawWcsdup(drive_root);
+#else
             pathconfig->prefix = _PyMem_RawWcsdup(separator);
+#endif
             if (pathconfig->prefix == NULL) {
                 return _PyStatus_NO_MEMORY();
             }
@@ -788,6 +810,27 @@ search_for_exec_prefix(PyCalculatePath *
     return _PyStatus_OK();
 }
 
+#ifdef MS_WINDOWS
+wchar_t*
+_Py_GetDLLPath(void)
+{
+    wchar_t dll_path[MAXPATHLEN+1];
+    memset(dll_path, 0, sizeof(dll_path));
+
+#ifdef Py_ENABLE_SHARED
+    extern HANDLE PyWin_DLLhModule;
+    if (PyWin_DLLhModule) {
+        if (!GetModuleFileNameW(PyWin_DLLhModule, dll_path, MAXPATHLEN)) {
+            dll_path[0] = 0;
+        }
+    }
+#else
+    dll_path[0] = 0;
+#endif
+
+    return _PyMem_RawWcsdup(dll_path);
+}
+#endif /* MS_WINDOWS */
 
 static PyStatus
 calculate_exec_prefix(PyCalculatePath *calculate, _PyPathConfig *pathconfig)
@@ -845,7 +888,11 @@ calculate_set_exec_prefix(PyCalculatePat
         if (exec_prefix == NULL) {
             return _PyStatus_NO_MEMORY();
         }
-
+#ifdef _WIN32
+        wchar_t drive_root[3];
+        memset(drive_root, 0, sizeof(drive_root));
+        wcsncpy(drive_root, exec_prefix, 3);
+#endif
         reduce(exec_prefix);
         reduce(exec_prefix);
         reduce(exec_prefix);
@@ -859,7 +906,11 @@ calculate_set_exec_prefix(PyCalculatePat
 
             /* The exec_prefix is the root directory, but reduce() chopped
                off the "/". */
+#ifdef _WIN32
+            pathconfig->exec_prefix = _PyMem_RawWcsdup(drive_root);
+#else
             pathconfig->exec_prefix = _PyMem_RawWcsdup(separator);
+#endif
             if (pathconfig->exec_prefix == NULL) {
                 return _PyStatus_NO_MEMORY();
             }
@@ -1191,10 +1242,12 @@ calculate_argv0_path(PyCalculatePath *ca
     }
 #endif
 
+#if HAVE_READLINK
     status = resolve_symlinks(&calculate->argv0_path);
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
+#endif
 
     reduce(calculate->argv0_path);
 
@@ -1364,6 +1417,14 @@ calculate_module_search_path(PyCalculate
 
     bufsz += wcslen(calculate->zip_path) + 1;
     bufsz += wcslen(calculate->exec_prefix) + 1;
+#ifdef MS_WINDOWS
+    if (_Py_isabs(calculate->prefix)) {
+        bufsz += wcslen(calculate->prefix) + 1;
+    }
+    if (_Py_isabs(calculate->argv0_path)) {
+        bufsz += wcslen(calculate->argv0_path) + 1;
+    }
+#endif
 
     /* Allocate the buffer */
     wchar_t *buf = PyMem_RawMalloc(bufsz * sizeof(wchar_t));
@@ -1391,7 +1452,7 @@ calculate_module_search_path(PyCalculate
 
         if (!_Py_isabs(defpath)) {
             wcscat(buf, calculate->prefix);
-            if (prefixsz >= 2 && calculate->prefix[prefixsz - 2] != SEP &&
+            if (prefixsz >= 2 && !is_sep(calculate->prefix[prefixsz - 2]) &&
                 defpath[0] != (delim ? DELIM : L'\0'))
             {
                 /* not empty */
@@ -1412,6 +1473,16 @@ calculate_module_search_path(PyCalculate
         defpath = delim + 1;
     }
     wcscat(buf, delimiter);
+#ifdef MS_WINDOWS
+    if (_Py_isabs(calculate->prefix)) {
+        wcscat(buf, calculate->prefix);
+        wcscat(buf, delimiter);
+    }
+    if (_Py_isabs(calculate->argv0_path)) {
+        wcscat(buf, calculate->argv0_path);
+        wcscat(buf, delimiter);
+    }
+#endif
 
     /* Finally, on goes the directory for dynamic-load modules */
     wcscat(buf, calculate->exec_prefix);
diff -rupN --no-dereference Python-3.10.9/Python/fileutils.c Python-3.10.9-new/Python/fileutils.c
--- Python-3.10.9/Python/fileutils.c	2022-12-06 19:31:21.000000000 +0100
+++ Python-3.10.9-new/Python/fileutils.c	2022-12-08 09:37:03.419024952 +0100
@@ -1976,13 +1976,21 @@ _Py_wrealpath(const wchar_t *path,
 #endif
 
 
-#ifndef MS_WINDOWS
 int
 _Py_isabs(const wchar_t *path)
 {
-    return (path[0] == SEP);
-}
+#ifdef MS_WINDOWS
+    size_t i = wcslen(path);
+    if (i >= 3) {
+        if (iswalpha(path[0]) && path[1] == L':' && (path[2] == SEP || path[2] == ALTSEP)) {
+            return 1;
+        }
+    }
+    return 0;
+#else
+    return path[0] == SEP;
 #endif
+}
 
 
 /* Get an absolute path.
diff -rupN --no-dereference Python-3.10.9/Python/pathconfig.c Python-3.10.9-new/Python/pathconfig.c
--- Python-3.10.9/Python/pathconfig.c	2022-12-06 19:31:21.000000000 +0100
+++ Python-3.10.9-new/Python/pathconfig.c	2022-12-08 09:37:03.420024952 +0100
@@ -15,6 +15,11 @@
 extern "C" {
 #endif
 
+#ifdef __MINGW32__
+// Include windows.h for MAXPATHLEN instead of overriding it in osdefs.h
+#include <windows.h>
+#endif
+
 
 _PyPathConfig _Py_path_config = _PyPathConfig_INIT;
 
@@ -227,7 +232,7 @@ _PyPathConfig_AsDict(void)
 
     {
         wchar_t py3path[MAX_PATH];
-        HMODULE hPython3 = GetModuleHandleW(PY3_DLLNAME);
+        HMODULE hPython3 = GetModuleHandleW("python3");
         PyObject *obj;
         if (hPython3
             && GetModuleFileNameW(hPython3, py3path, Py_ARRAY_LENGTH(py3path)))