If the vi is really vim, the try this in command mode (hit the esc key a couple of times to make sure):
If your prompt is colorized, that's probably coming from /etc/profile but possibly some junk in your ~/.bash_profile or ~/.bashrc (depends on what RedHat dumps in your $HOME).
Try resetting PS1
PS1="\u@\h \$ " produces user@host $
There is no standard bash setting for colors.