Internet navigation problems.

On my office network none of the computers connected to it have problems surfing the web, except my own. Pages fail to load 75% of the time, I use Google Chrome and Firefox but they both have the same problem. I've scanned my pc for malware and viruses using Malwarebytes and Bitdefender (separately of course) and they've come back clear. I've reset the tcp ip stack (a pain in Windows 8) taking full control of netsh via the regedit key (running it as admin), then wiping the wifi profile, following with a dns flush and finalizing with restarting the computer. Once restarted I can navigate the internet problem free for a few pages and then I go back to having issues. I am not an IT guy or anything of the sort, I just read a lot. But I've got to say I'm at a loss. I can't reinstall Windows 8 because I don't have a disc or a partition (upgraded from Win7 to 8 pro online, which I admit was a huge mistake). Any and all help is greatly appreciated.

I am running on:

Windows 8.1 Pro
AMD Athlon 2 P320 Dual Core Processor 2.10Ghz
8.00GB RAM, 64 bit OS, x64 processor.