let's first look at what you need to do w/ music stuff...
1. transfer from recorder to pc can be done w/ Explorer as the PMD is seen as another drive
2. editing/sample rate conversion/bit-depth reduction can all be done with wavelab, sound forge, cool edit, etc...which can be found cheaply (i can loan you a disc if you need it also)
3. tracking = cdwave = free
4. burning = nero or feurio or possibly whatever came with the dell (sonicrecord is what they give for free i think, it works, you just have to go into the options once and make sure disc-at-once is selected to remove gaps). nero adds 2sec gaps by default so you have to manually remove them before burning every time.
5. dvd-a = dvd-audiofile, search this forum for it, very easy to use
6. compressing/decompressing = FLAC frontend, mkwACT (for shn)
since you're not actually using this for recording, but rather file-transfer, editing, burning, sharing, etc, you don't need to tweak all that much. you say it won't be hooked up to the internet, but you're going to want to have the ability to access the 'net for downloading these programs, downloading windows updates, etc...so you'll want to have at least anti-virus software on it...if you want to use it to stream audio (like through a squeezebox type of unit) it will need to be networked and unless you want to turn off internet access you're pretty much going to be connected....