Many things can cause crashing,such as hardware,heat and infections.
Have you tried system restore?
Try Trend Micro PC-cillin and AVG ANTI SPYWARE in safe mode.
As a last resort disable system restore,scan in safe mode,then enable system restore,then scan in norm mode.
My desktop computer which is a Dell XPS gen 4 continually crashes. Unfortunately, my childresn have used the computer and gone all over the Internet- gosh knows what this has done. I have Trend Micro PC-cillin and a registry cleaning program. I have also uninstalled all unused prgrams so that only the essentials are there. Are there any truly good optimization programs or are the "new" online offers I have heard on the radio worthwhile. I am afraid of turning my computer over to someone online for security purposes. Also all drivers and bios have been updated. Win XP Pro operating system.