Windows XPwill not open except in Safe Mode

[curiouser]

This is my granddaughters computer.  We both have Toshiba Laptops.  She said two days ago there was an upgrade and she ok'd it.  The next day she could not get her computer to start normally.  I have tried to recover to an earlier date, have tried to recover the last normal start.  None of this works.  It will open up sometimes in the safemode, but of course not all of her settings are there, and we can not get the wireless connect to open up the internet.  I have been doing research on how to correct this problem, but have not found the solution yet.  Can someone please help?  I am on my computer, so I can try suggestions from here.
Thanks so much!
S.

[Sid]

Have you tried a Virus scan in safe-mode?

[patio]

Proper System Restore in Safe Mode

[curiouser]

well there seems to be a common thread going here with all of these subjects.  It is that XP has a problem.  Virus? unstable download? who knows for sure, the problem is we all seem to be having this problem.  My granddaughters computer was not protected by anitvirus program.  Mine is.  I have been getting the notice that a new hardward (video controller) has been detected when I restart my computer.  I have not added anything to my computer in a while now.  I have just been closing the upload now request and have gone about my business. 
Today, i went into my control panel, systems, drivers and have removed the ? that show for the other devices.  when i restarted they were back again. 
My computer is a laptop, 512M XP home, not sure what else you will need to know.
where can we find out if there is a real XP problem, or if this is a virus?  I am getting ready to run scan on my computer here real soon.

[GX1_Man]

My granddaughters computer was not protected by anitvirus program. 

And then she downloaded something and you wonder why there was a problem? Hardly XP's fault.

My computer is a laptop, 512M XP home, not sure what else you will need to know.

Service Pack installed? Computer model? Age of the machines? What specifically is loaded on each for virus and spyware protection? Stuff like that.