That motherboard was made by the FIC motherboard company of America... founded in 1980. We will be back in the morning with some recommendations for your FIC K7MNF-64 replacement.
Here is what I belive is your current configuration, and possibilities:
FIC K7MNF-64 nVidia nForce 2 Socket A mATX Motherboard with nVidia nForce 2 Chipset.
Socket A processor socket for AMD Duron, AMD Athlon XP, and AMD Sempron processors.
The mATX form factor (also called micro-ATX or uATX) has 20-pin ATX power connector and 4-pin ATX12V power connector
It will handle 266/333/400 MHz Front Side Bus (FSB) cpus and memory
Supports up to 2 GB RAM 266/333/400 (aka: PC2100/PC2700/PC3200)
Two (2) IDE controllers, and a floppy controller
Integrated video
Realtek ALC655 AC'97 audio codec
Integrated 10/100 Ethernet controller
Expansion Slots:
One (1) 4x/8x AGP slot
Three (3) PCI slots
Two (2) 184-pin DIMM slots
I/O Ports:
Two (2) PS/2 ports
One (1) 9-pin standard serial port
One (1) 25-pin standard parallel port
Eight (8) USB ports (four on back and four via header)
One (1) RJ-45 standard Ethernet jack
Line-in, microphone and line-out jacks
Supported Processors (do you know which one you have?)
AMD Duron 1.6 - 1.8 GHz with 266 MHz FSB
Athlon XP Palomino Core: 1500+ - 2100+ with 266 MHz FSB
Athlon XP Thoroughbred Core: 1700+ - 2700+ with 266/333 MHz FSB
Athlon XP Barton Core: 2500+ - 3200+ with 333/400 MHz FSB
AMD Sempron 3000 + and up
Look on
www.tigerdirect.com,
www.directron.com,
www.newegg.com,
www.outpost.com,
www.techdepot.com,
www.cdw.com,
www.pcmall.com,
www.pcconnections.com,
www.krex.com, and other such sites.
It is actually a board old enough that you might do better, and cheaper, starting over.
Search each of the above sites for motherboard/cpu combos... Then check back with us for which are deals and which should be avoided.
More in the morning.