You might want to try install Red Hat 8.0 and then upgrade your XFree86 packages. Intel 845G is not supported until v4.3. However, the driver is already available in pre-release version 4.2.99.3. The packages can be downloaded here
ftp://ftp.redhat.com/pub/redhat/linux/rawhide/i386/RedHat/RPMS
I suspect that the XFree86 packages on Red Hat 8.1beta1 also supports Intel 845G as it is listed in the drivers section. The version I have here is v4.2.99.2