Seems virus is preventing login

[Flower Gardener]

One of my PCs must have picked up a virus or a file is corrupted. When I
click on the user login button, the disk trundles for a few seconds then
tells me that Windows is saving the user information. I am returned to the
user login screen. And so on.

The PC also will not boot from a Windows CD even though the boot sequence is
set to boot from the CD.

How can I fix this PC without losing any files on it?

 

[Guest]

At start up,tap the F8 key,select safe mode,enter as administrator.