Erm, is there anything that is common to the freeze i.e. are you doing the same thing or using the same app when it freezes ?
Also, is it mandrake 10 community or mandrake 10 official?
Plus something to have a look at it the nvidia.com site. They have (from memory) some board/chip drivers as well as the graphic's driver - maybe that need's updating.
If you are using mandy 10 community, have you installed all the updates ?
Sorry if these aren't much help, but they may be thing's that point you in the right direction to start looking (though that's easy for me to say, because personally, I haven't had many problems with mandrake - lucky? don't know).
p.s. If you try the "newbie's tried and tested solution" i.e. the "re-install", then go for mandrake's default's, kde, lilo, etc. Well the way I usually explain it is when you get the package selection box, then just select all the stuff down the left (except LSB if you want a 2.6 kernel/LSB is you want a 2.4 kernel, I prefer 2.6) and only kde from the bottom of the right hand side, let it install (no to server stuff, you can always do that later) then tell it no to updates, complete the install etc then boot back into it, and in the mandrake control centre (configure my computer) software manager>updates check the bugfixes, security and normal updates and then install all the updates (which may take sometime if either there's lots or you have a slow connection) then see if you still have the freezing problem.