Major download speed problems, can't seem to find a solution

[gunanatomy]

Windows Vista, D-Link DIR-655

Avast antivirus, Super Antispyware, Spybot Search and Destroy installed

ISP is Northwestel.net

Network status: Sometimes yellow triangle, sometimes green checkmark in circle

Port is forwarded and open

Speed test: D/L speed: 3617 Kb/s, U/L speed: 369 Kb/s (dslreports.com)

lowering net.max_halfopen: 4

lowering bt.connect_speed: 10

DHT disabled

UPnP and NAT-PMP disabled

peer.resolve_country: false

bt.transp_disposition: 5

max. global number of connections: 50

Current settings: D: 400kB/s, U: 17kB/s

I've tried nearly everything I can find, short of a patch because I'm not 100% comfortable with doing that yet. I've set up a static IP, forwarded the port and everything. Checker says port is open. Speeds hover between 2.0 and 0.1 kB/s, but if I screw around with the download/upload settings and then restart my computer, speeds will shoot up to 250 kB/s and then drop back down within a few seconds, regardless of how many available seeders. Glasnost says my ISP isn't throttling BitTorrent. I can occasionally get the speed to stay around 20-50 kB/s, but rarely and randomly. It doesn't seem to matter what my settings are, nothing changes significantly or for any length of time.

Please, any help or advice would be greatly appreciated. Thanks.

[Switeck]

Do you get the same horrible results on the test torrents mentioned in 1st link in my signature?

[gunanatomy]

Yes, it doesn't matter what I'm trying to download, it's always the same problems.

[Switeck]

Either a misconfigured "learning" software firewall, bad drivers (overloading), or a bad ISP...those are what I deem most likely in no particular order.