One note about your Mandrake install... I have a similar setup (Mandrake 7.0 and Windows 98) and it works fine, but i hosed the 98 side the first time i did it. As merlin said, you have to edit lilo or possibly grub in your case to recognize the windows boot record.

Secondly, you can usually choose whether you will start up in the text-based OS or the graphic based OS... personally, i like the text-based because it's easy to do some quick and easy tasks before i head into the graphical based side. If you're not comfortable with the text-based, you might want to familiarize yourself with it, because it's the most powerful portion of Linux and you can become very efficient and productive with it.

Personally, I'd stick with an AMD processor, but that's just me... if i had to pick betweent the PIII and P4, or even (the dreaded) celeron, i'd say it's based on your needs and funds.

I'm guessing you're talkin about a command prompt during the install... which with mandrake, i'm not sure you can do, unless you do the entire instill from the command line (which again, i'm not sure if you can do that)