Earlier tonight I was on the internet when I noticed my computer was going a bit slow so I restarted it. However, after the Dell loading screen and before the WINDOWS loading screen, the following message appeared:
"Non-system disk or disk error. Replace and press any key when ready"
I have tried pressing every key but the message keeps RECURRING, and I don't know what to do. I have a Windows XP Dell computer that has a current Norton Antivirus version so I don't think it's a virus, but I am not sure. If you need any other information just let me know.

Thanks for any help!Usually that is a sign of a floppy left in the drive, or a failed hard disk or IDE controller.

Download the diagnosotics from the Dell website or from the hard drive manufacturer's WEB site to test.

Is the hard drive seen in the BIOS? (F2 setup) What is the service tag of the machine (also in the  BIOS, or affixed to the machine)?Yes, there was a floppy disk left in the drive. My brother had left it in there. I feel like an idiot now. Thank you very much!I know because I've done it too!