Sadly, I must say that I'm not a 100% Linux man just yet, but I've installed MEPIS on a separate hard drive and dual-booting alongside XP Pro. If more support for Linux games was available, I might make the transition.

Anyway, when I boot my system, Grub is by default on Linux. Is there a GUI interface in MEPIS where I can change the default OS? I've looked and can't find one.

You are saying that your GRUB correctly boots both Linux and Windows XP, but you want the default selection to be Windows ... If so, open an editor such as KWrite as root, and edit /boot/grub/menu.lst

AFTER you edit it, it should look something like this:
=================================================================================
timeout 15
color cyan/blue white/blue
foreground ffffff
background 0639a1
gfxmenu /boot/grub/message

title Windows at hda1
rootnoverify (hd0,0)
chainloader +1

title MEPIS at hda2, kernel 2.6.12.3-onion1
kernel (hd0,1)/boot/vmlinuz-2.6.12.3-onion1 root=/dev/hda2 nomce psmouse.proto=imps quiet splash=verbose vga=791
initrd (hd0,1)/boot/initrd.splash

title MEMTEST
kernel /boot/memtest86.bin

=================================================================================
That is, the default is the top entry -- you're reversing the order of the entries ...

-- Mike
===
Post to http://www.mepislovers.org

Great forum!

Alternatively you could do this in this link

http://www.mepislovers-wiki.org/inde...the_boot_order