I have a Toshiba laptopo. When I switch it on the screen flashes and there appears to be a flower on the screen. It will not respond to anything. It will switch off but as soon as you switch it back on the same screen appears.
if you have windows repair disk, then you can choose startup repair
you can open cmd windows
type: sfc /scannow and hit enter wait the scan to finish
type: chkdsk /r and hit enter wait the scan to finish
if laptop infected there are some live cd with antimalware with you can try ESET SysRescue Live CD/USB creator it comes with team viewer