1. Turn it off and on again.
2. Use system restore to when it worked. How is on the web so I don't write how. A few disable that and I can't imagine why since SR (system restore) is there to avoid a fresh install.
3. Test these on other PCs.
My computer suddenly refuses to recognize my two printers (HP laserjet & Canon Color) and my Seagate external backup. Although it recognizes my scanner. Both were working yesterday. I'm windows 7. Thanks for help.