I would say yes, one more PC that is not in a landfill

- you can still get the am2 / ddr2 boards like this one
ASRock A785GM-LE AM3/AM2+/AM2 AMD 785G Micro ATX $54+$7shipping the only downside the
original MCP61PM-HM (Nettle2) motherboard has 4 dimms and most likely 3gb in 2x1g and 2x512m config so with 2 dimms on the replacement you are only left with 2gb total (hard to find 4dimm boards in ddr2 nowadays, would be ideal replacement). Another downside, the Vista OEM license may not be transferable to the new motherboard BUT I have heard of people calling MS for reactivation after explaining the system board failure and all is well.
If not, then:
- win7 home is a welcome upgrade
- win home server will work well, the 1tb drive will make for good backups of all other windows desktop/laptops you happen to have
- linux should work no problem on that hardware
- make a decent HTPC (since it has DVI output) with whatever OS and XBMC running
hope this gives you some ideas, cheers