Removed unnecessary HANDLE typecasts.

diff --git a/dlls/msacm/filter.c b/dlls/msacm/filter.c
index 6be5586..6389125 100644
--- a/dlls/msacm/filter.c
+++ b/dlls/msacm/filter.c
@@ -100,7 +100,7 @@
 	    mmr = MMSYSERR_INVALPARAM;
 	    break;
 	}
-	if (had == (HACMDRIVER)NULL) {
+	if (had == NULL) {
 	    PWINE_ACMDRIVERID		padid;
 
 	    mmr = ACMERR_NOTPOSSIBLE;
@@ -298,7 +298,7 @@
 
     switch (fdwDetails) {
     case ACM_FILTERTAGDETAILSF_FILTERTAG:
-	if (had == (HACMDRIVER)NULL) {
+	if (had == NULL) {
 	    mmr = ACMERR_NOTPOSSIBLE;
 	    for (padid = MSACM_pFirstACMDriverID; padid; padid = padid->pNextACMDriverID) {
 		/* should check for codec only */
@@ -320,7 +320,7 @@
 	break;
 
     case ACM_FILTERTAGDETAILSF_LARGESTSIZE:
-	if (had == (HACMDRIVER)NULL) {
+	if (had == NULL) {
 	    ACMFILTERTAGDETAILSW	tmp;
 	    DWORD			ft = paftd->dwFilterTag;
 
diff --git a/dlls/msacm/format.c b/dlls/msacm/format.c
index a608d50..dd3b769 100644
--- a/dlls/msacm/format.c
+++ b/dlls/msacm/format.c
@@ -143,7 +143,7 @@
     affd.hWnd = hWnd;
     affd.mode = WINE_ACMFF_TAG;
 
-    acmFormatTagEnumA((HACMDRIVER)0, &aftd, MSACM_FillFormatTagsCB, (DWORD)&affd, 0);
+    acmFormatTagEnumA(NULL, &aftd, MSACM_FillFormatTagsCB, (DWORD)&affd, 0);
     SendDlgItemMessageA(hWnd, IDD_ACMFORMATCHOOSE_CMB_FORMATTAG, CB_SETCURSEL, 0, 0);
     return TRUE;
 }
@@ -166,7 +166,7 @@
 					    CB_GETCURSEL, 0, 0),
 			(DWORD)affd.szFormatTag);
 
-    acmFormatTagEnumA((HACMDRIVER)0, &aftd, MSACM_FillFormatTagsCB, (DWORD)&affd, 0);
+    acmFormatTagEnumA(NULL, &aftd, MSACM_FillFormatTagsCB, (DWORD)&affd, 0);
     SendDlgItemMessageA(hWnd, IDD_ACMFORMATCHOOSE_CMB_FORMAT, CB_SETCURSEL, 0, 0);
     return TRUE;
 }
@@ -189,7 +189,7 @@
 					    CB_GETCURSEL, 0, 0),
 			(DWORD)affd.szFormatTag);
 
-    acmFormatTagEnumA((HACMDRIVER)0, &aftd, MSACM_FillFormatTagsCB, (DWORD)&affd, 0);
+    acmFormatTagEnumA(NULL, &aftd, MSACM_FillFormatTagsCB, (DWORD)&affd, 0);
     return affd.ret;
 }
 
@@ -332,7 +332,7 @@
 	    mmr = MMSYSERR_INVALPARAM;
 	    break;
 	}
-	if (had == (HACMDRIVER)NULL) {
+	if (had == NULL) {
 	    PWINE_ACMDRIVERID		padid;
 
 	    mmr = ACMERR_NOTPOSSIBLE;
@@ -552,7 +552,7 @@
     adfg.pwfxDst = pwfxDst;
     adfg.cbwfxDst = cbwfxDst;
 
-    if (had == (HACMDRIVER)NULL) {
+    if (had == NULL) {
 	PWINE_ACMDRIVERID	padid;
 
 	/* MS doc says: ACM finds the best suggestion.
@@ -621,7 +621,7 @@
 
     switch (fdwDetails) {
     case ACM_FORMATTAGDETAILSF_FORMATTAG:
-	if (had == (HACMDRIVER)NULL) {
+	if (had == NULL) {
 	    for (padid = MSACM_pFirstACMDriverID; padid; padid = padid->pNextACMDriverID) {
 		/* should check for codec only */
 		if (!(padid->fdwSupport & ACMDRIVERDETAILS_SUPPORTF_DISABLED) &&
@@ -641,7 +641,7 @@
 	break;
 
     case ACM_FORMATTAGDETAILSF_INDEX:
-	if (had != (HACMDRIVER)NULL) {
+	if (had != NULL) {
 	    PWINE_ACMDRIVER	pad = MSACM_GetDriver(had);
 
 	    if (pad && paftd->dwFormatTagIndex < pad->obj.pACMDriverID->cFormatTags)
@@ -650,7 +650,7 @@
 	break;
 
     case ACM_FORMATTAGDETAILSF_LARGESTSIZE:
-	if (had == (HACMDRIVER)NULL) {
+	if (had == NULL) {
 	    ACMFORMATTAGDETAILSW	tmp;
 	    DWORD			ft = paftd->dwFormatTag;
 
diff --git a/dlls/msacm/imaadp32/imaadp32.c b/dlls/msacm/imaadp32/imaadp32.c
index 2592d1c..a8117ff 100644
--- a/dlls/msacm/imaadp32/imaadp32.c
+++ b/dlls/msacm/imaadp32/imaadp32.c
@@ -476,7 +476,7 @@
     add->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
     add->cFormatTags = 2; /* PCM, IMA ADPCM */
     add->cFilterTags = 0;
-    add->hicon = (HICON)0;
+    add->hicon = NULL;
     MultiByteToWideChar( CP_ACP, 0, "WINE-ADPCM", -1,
                          add->szShortName, sizeof(add->szShortName)/sizeof(WCHAR) );
     MultiByteToWideChar( CP_ACP, 0, "Wine IMA ADPCM converter", -1,
diff --git a/dlls/msacm/msacm32_main.c b/dlls/msacm/msacm32_main.c
index 327b709..6b7b39b 100644
--- a/dlls/msacm/msacm32_main.c
+++ b/dlls/msacm/msacm32_main.c
@@ -52,7 +52,7 @@
         MSACM_UnregisterAllDrivers();
         HeapDestroy(MSACM_hHeap);
         MSACM_hHeap = (HANDLE)NULL;
-        MSACM_hInstance32 = (HINSTANCE)NULL;
+        MSACM_hInstance32 = NULL;
 	break;
     case DLL_THREAD_ATTACH:
 	break;
@@ -176,7 +176,7 @@
 	break;
 
     case ACM_METRIC_MAX_SIZE_FORMAT:
-	if (hao == (HACMOBJ)NULL) {
+	if (hao == NULL) {
 	    for (padid = MSACM_pFirstACMDriverID; padid; padid = padid->pNextACMDriverID) {
 		if (!(padid->fdwSupport & ACMDRIVERDETAILS_SUPPORTF_DISABLED)) {
 		    for (i = 0; i < padid->cFormatTags; i++) {
diff --git a/dlls/msacm/msadp32/msadp32.c b/dlls/msacm/msadp32/msadp32.c
index ce5d32b..a7a8c63 100644
--- a/dlls/msacm/msadp32/msadp32.c
+++ b/dlls/msacm/msadp32/msadp32.c
@@ -322,7 +322,7 @@
     add->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
     add->cFormatTags = 2; /* PCM, MS ADPCM */
     add->cFilterTags = 0;
-    add->hicon = (HICON)0;
+    add->hicon = NULL;
     MultiByteToWideChar( CP_ACP, 0, "WINE-MS ADPCM", -1,
                          add->szShortName, sizeof(add->szShortName)/sizeof(WCHAR) );
     MultiByteToWideChar( CP_ACP, 0, "Wine MS ADPCM converter", -1,
diff --git a/dlls/msacm/msg711/msg711.c b/dlls/msacm/msg711/msg711.c
index 637eeb9..18023ad 100644
--- a/dlls/msacm/msg711/msg711.c
+++ b/dlls/msacm/msg711/msg711.c
@@ -659,7 +659,7 @@
     add->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
     add->cFormatTags = 3; /* PCM, G711 A-LAW & MU-LAW */
     add->cFilterTags = 0;
-    add->hicon = (HICON)0;
+    add->hicon = NULL;
     MultiByteToWideChar( CP_ACP, 0, "WINE-G711", -1,
                          add->szShortName, sizeof(add->szShortName)/sizeof(WCHAR) );
     MultiByteToWideChar( CP_ACP, 0, "Wine G711 converter", -1,
diff --git a/dlls/msacm/pcmconverter.c b/dlls/msacm/pcmconverter.c
index 891995f..3ff5466 100644
--- a/dlls/msacm/pcmconverter.c
+++ b/dlls/msacm/pcmconverter.c
@@ -719,7 +719,7 @@
     add->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CONVERTER;
     add->cFormatTags = 1;
     add->cFilterTags = 0;
-    add->hicon = (HICON)0;
+    add->hicon = NULL;
     MultiByteToWideChar( CP_ACP, 0, "WINE-PCM", -1,
                          add->szShortName, sizeof(add->szShortName)/sizeof(WCHAR) );
     MultiByteToWideChar( CP_ACP, 0, "Wine PCM converter", -1,
diff --git a/dlls/msacm/stream.c b/dlls/msacm/stream.c
index 8e4c28e..498aa47 100644
--- a/dlls/msacm/stream.c
+++ b/dlls/msacm/stream.c
@@ -237,7 +237,7 @@
     }
 errCleanUp:
     if (phas)
-	*phas = (HACMSTREAM)0;
+	*phas = NULL;
     HeapFree(MSACM_hHeap, 0, was);
     TRACE("=> (%d)\n", ret);
     return ret;
diff --git a/dlls/msacm/winemp3/mpegl3.c b/dlls/msacm/winemp3/mpegl3.c
index e475455..c0221f6 100644
--- a/dlls/msacm/winemp3/mpegl3.c
+++ b/dlls/msacm/winemp3/mpegl3.c
@@ -177,7 +177,7 @@
     add->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
     add->cFormatTags = 2; /* PCM, MPEG3 */
     add->cFilterTags = 0;
-    add->hicon = (HICON)0;
+    add->hicon = NULL;
     MultiByteToWideChar( CP_ACP, 0, "WINE-MPEG3", -1,
                          add->szShortName, sizeof(add->szShortName)/sizeof(WCHAR) );
     MultiByteToWideChar( CP_ACP, 0, "Wine MPEG3 decoder", -1,