Reformatted Computer, Abysmal Connection?

i reformatted my hard drive 3 weekends ago after getting a new ssd. i have my windows 7 and adobe cs5 installed on my ssd. everything else is on my trusty, old hard drive. when i re-formatted, i used an ultimate boot cd > darik's boot & nuke. it took 15 hours! if there was anything naughty on there then i sure as heck was determined to get rid of it.before i formatted i had the occasional internet hiccup (it's comcastic!) but nothing to cry about. but now...i literally can't do anything i used to do.downloading anything takes forever. there's constant hang-ups and time-outs.also i love to play games online, but this problem is causing me nothing but headaches. i've been playing fallout 3 lately and i'm constantly disconnected from windows live/steam because my connection is so poor.if i want to watch a Internet video then i have to have the foresight to buffer for a good time before i want to actually enjoy it. this goes for netflix as well, you can forget about watching anything on there... last night i wanted to watch a video with a friend. it was 12 minutes long. it took me 15 minutes to buffer...at 240p. pathetic right?

using skype is virtually impossible now too. i keep getting slow connection speed errors/messages and my friend and i look like we're 8-bit characters.!but the thing is...i swapped to skype last night on my phone before bed to talk with my friend and the connection seemed absolutely fine. no hiccups or bumps or anything. and the picture seemed crisp as could be (well, as far as my iphone 3gs can get anyway!)i keep getting "no internet access" errors when trying to connect to my router. my parents live across the street. since i used to live with them i still have the code for their internet. i'm using it now because it works better than my connection in the living room. how sad is that?

- searched forums! most everything i find points to spyware/malware/viruses. i could re-format again this weekend but i don't see how it's possible that anything naughty clung to my hard drive after using darik's boot & nuke 3 weekends ago;

- swapped out my router, same undesirable result;

- reset router and modem, that didn't seem to change anything;

- run memtest86, i did this test overnight, 8 hours later and there were 0 errors, so i know my ram isn't the issue...

i might be a bit ignorant when it comes to these things but i'm really at my wits end with this. it's been 3 weeks and i can't seem to figure out why my internet is so unreliable. and i did check on comcast's website, i'm at 80% of the cap for this month. so i haven't gone over.i swapped back to my connection to try and get a speedtest.net reading but i timed out each time after 5 minutes of trying to access that website. and well...i'm back on my parent's connection.