Internet issues

Ok,

I undersand this may not be the ideal sub-catagory to post this in but as I looked through I didn't see one specifically to house my current issue. This being the case I went with an OS forum. Anyways some background info, I'm currently experiancing some delay with my internet as of late. I own 4 computers and only this one is experiancing these problems so I'm assuming it's a system issue. I've ran defrag, disk cleaner, malware bytes and AVG (the most recent free-ware versions) to no avail. Ironically video games, etc. run perfectly on this rig as they always have but I'm noticing a delay in my internet browsing as I explained.

Now I'm aware this could be due to spyware, etc. that my anti-virus software isn't equipped to catch yet but when you take every precaution that you can think of it leaves you wondering; I'm a computer technician by the way so I would like to think I've considerd a lot of options here but I'm still being eluded by a real solution.

Spec-wise I'm running Windows 7 64-bit, I think 6 gigs of ram, an Nvidia 8400 gs or something card, etc. It's a year or two old system, the only actual purchased system I own as I usually just throw them together with bare bones kits. Oh and a dual core processor.

Anyone able to think of any solutions that I havn't? Also I have my internet options to delete browsing history, cookies, etc. upon closing windows so that shouldn't be an issue either.