There are so many things wrong with this it's hard to know where to start. You don't want to check an exe file, you want to check an ISO.
i thought i was checking the .iso file but using teh command feature along with the md5sume.exe. anyway thats all behind me.
instead of going tor a download manager i went for BitTorrent. this seems to be the right idea. following the advice from the download faq section i went for BitTornado. things seem to be going preety well, slow but steady and there have been a few stops/restarts in downloads but hopefully it'll do the md5 for me and things will be great!

If you have a router (and shame on you if you are running a high speed service without one, consider getting one right away. Tun off your computer now, go out and buy one. I mean this!) then you need to forward a few ports to your BitTorrent system. How you do this is router dependent and covered well here. You can just forward ports 6881 to 6889 to the IP address you will run BitTorrent from. My router, like almost all but the oldest routers, has a feature that lets outgoing traffic trigger port forwarding. This is very handy for me since I can set up BitTorrent as a "triger application" and then no matter what computer I run BitTorrent from, the proper ports get forwarded to it. So I just create a entry in the table that watches for trigger traffic, when it sees an outbound packet on ports 6881 to 6889 it forwards that range to the system that sent the outbound packet. All done.
i do have a router (belkin wifi 54g) i read the link you provided but would the port forwarding increase the speed and is it an aditional extra or a need to have bit of stuff. i just want the download to finish so i can burn the .iso (slowly at 4x) on Nero to get cracking!