I too can confirm this takes place...when the scan is about 75%-85% complete. It just hangs there and does nothing...here's my system info, if that helps:
OS Name Microsoft Windows XP Professional
Version 5.1.2600 Service Pack 3 Build 2600
OS Manufacturer Microsoft Corporation
System Manufacturer Gigabyte Technology Co., Ltd.
System Model EX58-UD3R
System Type X86-based PC
Processor x86 Family 6 Model 26 Stepping 4 GenuineIntel ~2664 Mhz
BIOS Version/Date Award Software International, Inc. F1, 12/10/2008
SMBIOS Version 2.4
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Locale United States
Hardware Abstraction Layer Version = "5.1.2600.5512 (xpsp.080413-2111)"
Time Zone Central Daylight Time
Total Physical Memory 4,096.00 MB
Available Physical Memory 2.74 GB
Total Virtual Memory 2.00 GB
Available Virtual Memory 1.96 GB
Page File Space 5.09 GB
Page File C:\pagefile.sys