diff --git a/collector/os.go b/collector/os.go
index 6af19159..aa914f39 100644
--- a/collector/os.go
+++ b/collector/os.go
@@ -4,15 +4,16 @@ package collector
 
 import (
 	"fmt"
+	"os"
 	"strings"
 	"time"
 
-	"github.com/prometheus-community/windows_exporter/headers/custom"
 	"github.com/prometheus-community/windows_exporter/headers/netapi32"
 	"github.com/prometheus-community/windows_exporter/headers/psapi"
 	"github.com/prometheus-community/windows_exporter/headers/sysinfoapi"
-	"github.com/prometheus-community/windows_exporter/log"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
+	"golang.org/x/sys/windows/registry"
 )
 
 func init() {
@@ -157,60 +158,63 @@ type Win32_OperatingSystem struct {
 }
 
 func (c *OSCollector) collect(ctx *ScrapeContext, ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
-	/*var dst []Win32_OperatingSystem
-	q := queryAll(&dst)
-	if err := wmi.Query(q, &dst); err != nil {
-		return nil, err
-	}
-
-	if len(dst) == 0 {
-		return nil, errors.New("WMI query returned empty result set")
-	}*/
-
-	product, buildNum := custom.GetProductDetails()
-
 	nwgi, _, err := netapi32.NetWkstaGetInfo()
 	if err != nil {
 		return nil, err
 	}
 
-	ch <- prometheus.MustNewConstMetric(
-		c.OSInformation,
-		prometheus.GaugeValue,
-		1.0,
-		fmt.Sprintf("Microsoft %s", product), // Caption
-		fmt.Sprintf("%d.%d.%s", nwgi.Wki102_ver_major, nwgi.Wki102_ver_minor, buildNum), // Version
-	)
-
 	gmse, err := sysinfoapi.GlobalMemoryStatusEx()
 	if err != nil {
 		return nil, err
 	}
 
-	ch <- prometheus.MustNewConstMetric(
-		c.PhysicalMemoryFreeBytes,
-		prometheus.GaugeValue,
-		float64(gmse.UllAvailPhys),
-	)
-
 	currentTime := time.Now()
-
-	ch <- prometheus.MustNewConstMetric(
-		c.Time,
-		prometheus.GaugeValue,
-		float64(currentTime.Unix()),
-	)
-
 	timezoneName, _ := currentTime.Zone()
 
-	ch <- prometheus.MustNewConstMetric(
-		c.Timezone,
-		prometheus.GaugeValue,
-		1.0,
-		timezoneName,
-	)
+	// Get total allocation of paging files across all disks.
+	memManKey, err := registry.OpenKey(registry.LOCAL_MACHINE, `SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management`, registry.QUERY_VALUE)
+	if err != nil {
+		return nil, err
+	}
+	pagingFiles, _, err := memManKey.GetStringsValue("ExistingPageFiles")
+	if err != nil {
+		return nil, err
+	}
 
-	fsipf, err := custom.GetSizeStoredInPagingFiles()
+	if err := memManKey.Close(); err != nil {
+		return nil, err
+	}
+
+	// Get build number and product name from registry
+	ntKey, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Windows NT\CurrentVersion`, registry.QUERY_VALUE)
+	if err != nil {
+		return nil, err
+	}
+	pn, _, err := ntKey.GetStringValue("ProductName")
+	if err != nil {
+		return nil, err
+	}
+
+	bn, _, err := ntKey.GetStringValue("CurrentBuildNumber")
+	if err != nil {
+		return nil, err
+	}
+
+	if err := ntKey.Close(); err != nil {
+		return nil, err
+	}
+
+	var fsipf float64 = 0
+	for _, pagingFile := range pagingFiles {
+		fileString := strings.ReplaceAll(pagingFile, `\??\`, "")
+		file, err := os.Stat(fileString)
+		if err != nil {
+			return nil, err
+		}
+		fsipf += float64(file.Size())
+	}
+
+	gpi, err := psapi.GetPerformanceInfo()
 	if err != nil {
 		return nil, err
 	}
@@ -220,21 +224,49 @@ func (c *OSCollector) collect(ctx *ScrapeContext, ch chan<- prometheus.Metric) (
 		return nil, err
 	}
 
-	var pfbPercent float64
+	// Get current page file usage.
+	var pfbRaw float64 = 0
 	for _, pageFile := range pfc {
 		if strings.Contains(strings.ToLower(pageFile.Name), "_total") {
-			pfbPercent = pageFile.Usage
-		} else {
 			continue
 		}
+		pfbRaw += pageFile.Usage
 	}
 
-	fpbNum := float64(fsipf) - (float64(fsipf) / float64(100) * pfbPercent)
+	// Subtract from total page file allocation on disk.
+	pfb := fsipf - (pfbRaw * float64(gpi.PageSize))
+
+	ch <- prometheus.MustNewConstMetric(
+		c.OSInformation,
+		prometheus.GaugeValue,
+		1.0,
+		fmt.Sprintf("Microsoft %s", pn), // Caption
+		fmt.Sprintf("%d.%d.%s", nwgi.Wki102_ver_major, nwgi.Wki102_ver_minor, bn), // Version
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.PhysicalMemoryFreeBytes,
+		prometheus.GaugeValue,
+		float64(gmse.UllAvailPhys),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.Time,
+		prometheus.GaugeValue,
+		float64(currentTime.Unix()),
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.Timezone,
+		prometheus.GaugeValue,
+		1.0,
+		timezoneName,
+	)
 
 	ch <- prometheus.MustNewConstMetric(
 		c.PagingFreeBytes,
 		prometheus.GaugeValue,
-		float64(fpbNum),
+		pfb,
 	)
 
 	ch <- prometheus.MustNewConstMetric(
@@ -258,11 +290,6 @@ func (c *OSCollector) collect(ctx *ScrapeContext, ch chan<- prometheus.Metric) (
 		float64(gmse.UllTotalVirtual),
 	)
 
-	gpi, err := psapi.GetLPPerformanceInfo()
-	if err != nil {
-		return nil, err
-	}
-
 	ch <- prometheus.MustNewConstMetric(
 		c.Processes,
 		prometheus.GaugeValue,
diff --git a/headers/custom/custom.go b/headers/custom/custom.go
deleted file mode 100644
index 752b33ec..00000000
--- a/headers/custom/custom.go
+++ /dev/null
@@ -1,54 +0,0 @@
-package custom
-
-import (
-	"log"
-	"os"
-	"strings"
-
-	"golang.org/x/sys/windows/registry"
-)
-
-// GetSizeStoredInPagingFiles returns the total size of paging files across all discs.
-func GetSizeStoredInPagingFiles() (int64, error) {
-	k, err := registry.OpenKey(registry.LOCAL_MACHINE, `SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management`, registry.QUERY_VALUE)
-	if err != nil {
-		return 0, err
-	}
-	pagingFiles, _, err := k.GetStringsValue("ExistingPageFiles")
-	if err != nil {
-		return 0, err
-	}
-
-	var size int64 = 0
-	for _, pagingFile := range pagingFiles {
-		fileString := strings.ReplaceAll(pagingFile, `\??\`, "")
-		file, err := os.Stat(fileString)
-		if err != nil {
-			return 0, err
-		}
-		size += file.Size()
-	}
-	return size, nil
-}
-
-// GetProductDetails returns the ProductName and CurrentBuildNumber values from the registry.
-func GetProductDetails() (string, string) {
-	k, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Windows NT\CurrentVersion`, registry.QUERY_VALUE)
-	if err != nil {
-		log.Fatal(err)
-	}
-	pn, _, err := k.GetStringValue("ProductName")
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	bn, _, err := k.GetStringValue("CurrentBuildNumber")
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	if err := k.Close(); err != nil {
-		log.Fatal(err)
-	}
-	return pn, bn
-}