I know a little if not a lot on chip-sets & the 845PE is regarded as one of the best if not the best, it is the fastest chip-set bar none. But it is not up to date as far as handling newer technologies go, so Intel has taken it further & added many features as time went on, if you look at Intel's lineup of mainstream or better chip-sets you will find many 845 derivatives such as this 845G, if your chip-set is an 845GV then it is more of a bottom line chip-set that did'nt make the cut, the (V) stands for value which is usually found on lower priced "value" computers. If it is not a GV model then the first thing I would look at is the MD5sum on the ISO CD images you downloaded to see if they are tainted.
Here is a link to a little Windows GUI utility that will do that for you,
http://www.toast442.org/md5/ , just click on the .exe then select "Generate Checksums" then drag & drop the ISO cd image into the window & wait a little bit then it will show the checksum number. Compare it to the one on the web site where you got your ISO image & if they do not match then you have a bad download.
Because as far as I'm concerned, Mandrake 10.1 should not have a problem with any type of 845 chip-set for the 845 family has been around for a while, it should be able to detect it & configure the X windows to come up with a display.