EXTREMELY Slow Speeds On PC But Not Laptop (Wireless)

Here is the problem... I have a PC which is connected to a router via Ethernet. It has been working perfectly for almost 6 months now but 2 hours ago the speeds dropped considerably. If I had to put it into perspective I'd say the speed is even slower than Internet running on a 28.8k modem.

I did nothing at all (as far as I know) to cause this considerable reduction in speed and it's getting really frustrating now because I can't find the cause. I've run all sorts of checks such as Ad-Aware, Zone Alarm, AVG Anti Spyware, AVG Free, Spybot etc but it hasn't found anything. I've also tried turning the router on & off restarting the PC, releasing & renewing the IP address in CMD but still can't find anything wrong with it.

Now if it wasn't for the following I'd probably assume that it was just the ISP but... The weird thing is it seems to run perfectly on the laptop downstairs (which I'm using to type this out) which is connected to the router via Wireless. The speed is as fast it always has been down here.

Anyway, I'd really appreciate any help regarding this as it's driving me nuts, thanks.

 

Start, Run, taskmgr. Check under Applications and Processes tabs to see what programs are running and what processes are running in the background. Have seen print spooler, among others, causing a slowdown, trying to send a document to a nonexistent printer.
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