Hi there
A few possibilities come to mind :
1. The new ram module (I assume this is the 512MB, right?) is incompatible with your original ram
2. The new module is incompatible with the motherboard
3. The new module (or socket) is faulty
4. The ram is incorrectly configured
5. You're running win9x on this system (although this doesn't appear to be true in your case, as mup.sys is a XP/2000 file)
If I were you, I would try the following things:
Remove the new module & make sure the system still boots OK with just the original ram installed
Remove the old ram & try booting the system with just the new ram
Run memtest86 to check for ram faults :
http://www.memtest.org/#downisoDownload the 'pre-compiled package for floppy(DOS/win)' version. This will create a bootable floppy disk with memtest on & is therefore independent of the systems OS.
Can you let us know the following system specs as well:
motherboard make/model
RAM type & speed of each ram module
If you don't know these, you can use everest to find out :
http://majorgeeks.co...tion_d4181.html