Computer won't start

Hi can anyone help with htis? I installed a new hard drive to my laptop a few weeks ago and it worked really well until yesterday when a couple of things happened. I installed Windows XP SP2 and later the same day my son borrowed my laptop and installed AOL Instant Messenger and probably visietd a few web-sites (myspace.com was one). When I then used the computer it kept shutting down and restarting. Then I got a blue screen saying something about a driver and beginning dump of physical memory. After that the only way to restart was to unhook the power and fire it up again. This worked a few times but now the computer won't boot at all. It just goes to a STOP message, says it can't find winsrv and it just sits there. Can anyone advise me please? Thanks

Boot to BIOS, look for and enable "load default settings"….reboot. If that doesnt work, put in your xp installation cd and boot up..make sure in BIOS that the boot order is set to boot form cd drive before the harddrive. When it asks "Press Any Key To Boot From CD"… do so. (you only have a short time (5 seconds) to do this). It will load setup files, then start the installation process. It will ask you if you want to repair a version of windows found or install a fresh copy…choose to Install a fresh copy.. follow instructions till it asks you one more time if you want to repair. If you get to the partitioning process you've gone TO FAR .. DO NOT go any further and you need to press F3 to quit..If it only asks you one time to repair then you dont have the automatic repair option. The first time it asks you, it lets you use the repair console and unless you know which file/files need to be replaced/repaired and were they are on the cd and which folder top copy them to then I wouldnt mess that. I am not sure which, XP Home or XP Pro offers this but one of them does.

Thanks. How do I boot to BIOS? Sorry I'm pretty hopeless with the computer.

I tried this but the computer won't boot. It won't install set up files although it starts to. I get various error messages telling me files are corrupt or missing. it then says press any key to exit. When i do that the PC restarts and gives me another STOP message. I then have to unplug power to turn it off. When i reconnect pwer and try to restart it goes through the same routine of error messages, restarts and crashes. Any thoughts?