My Computer gets Stuck after a small time Booting up?

This is the system summary

OS NameMicrosoft Windows XP Professional

Version5.1.2600 Service Pack 2 Build 2600

OS ManufacturerMicrosoft Corporation

System NameVARUNA

System ManufacturerMSI

System ModelMS-7043

System TypeX86-based PC

Processorx86 Family 15 Model 4 Stepping 1 GenuineIntel ~2410 Mhz

BIOS Version/DateAmerican Megatrends Inc. Version 07.00T, 02/04/2001

SMBIOS Version2.3

Windows DirectoryC:\WINDOWS

System DirectoryC:\WINDOWS\system32

Boot Device\Device\HarddiskVolume1

LocaleUnited Kingdom

Hardware Abstraction LayerVersion = ''5.1.2600.2180 (xpsp_sp2_rtm.040803-2158)''

User NameVARUNA\Administrator

Time ZoneIndia Standard Time

Total Physical Memory768.00 MB

Available Physical Memory429.44 MB

Total Virtual Memory2.00 GB

Available Virtual Memory1.96 GB

Page File Space1.83 GB

Page FileC:\pagefile.sys

I have defragmented and Avg free edition,spyware doctor free edition,yahoo antiSpy installed

My Computer gets Stuck after a small time Booting up?adware

Does it start up in same mode?

(press F8 on restart and select safe mode from the menu)

If it does, try doing a system restore (Start\Accessories\System Tools\System Restore).

Did it happen after you install a 3rd party software, uninstall it and see if it helps.