I am in serious trouble if I can't sort this before my son gets home from school.

His PC is a Dell optiplex 745 running WinXP

He asked me to change his default browser back to IE as he had tried Google and didn't like it. So I did, then did a restart but now it gets to the blue screen with his name icon but when I click on it it will not load the personal settings just does nothing. I tried control alt delete and it just went to the desktop background picture but no icons, and then just freezes. I had to switch it off at the mains. I have tried 3 times now and it's the same every time.

I suppose it is a startup problem, but only having limited knowledge, I dare not do anything without a bit of advice in case I make it worse.

Can someone please help as Danny will be heartbroken (he's only 11) if I can't fix it.