Should I flash my BIOS?

To whom it may concern:
I have been working on a Gateway machine for the past week. Everytime I start the computer I receive the message “No Operating System found.” Then, from there I hit Ctrl+Alt+Del and it then boots into Windows, but it seems to take awhile. Then, everytime I boot up, I receive a message from my virus protection program (Inoculate) saying that the CMOS has changed, do you want to accept(a), ignore(i), or quit(q). Is something screwed up in my BIOS? When I check the settings, they all seem to be correct. Should I flash my BIOS? Please help.