I have 3 computers set up on a wireless network, and about 3 weeks ago I noticed a large decrease in internet speed. Being on a Westnet Bundled Pro(i) 1.5Mb to 20Mb/1Mb plan I was always averaging 5.9mbps download speed when testing at speedtest.net. However that speed dropped down to between .45 and 1.25mbps across all my computers, it was a very quick change, not a slow dying process, and I never worked out what triggered it. Recently I was able to rule out an ISP issue because I set my router to GDMT modulation mode, as it had been on MMODE. This instantly restored the speed to regular on 2 out of my 3 computers. However the main computer I use, frustratingly, is the only one still suffering severly reduced speeds. So, I have so far ruled out it being an ISP problem, the drivers are up to date according the manufacturers website, nothing I have run has found any viruses or any other form of malware and I even went so far as to check the card hadn't somehow unscrewed itself and got loose in its slot. The only other relevant piece of information I can think of is ever since I changed the modems modulation type to GDMT my main computer has been suffering from disconnects from the network, which haven't affected the computer sitting on the table right next to it, and the network will not re-establish connection until I reset the computer or hard reset the router. Does anyone have any ideas as to what could be causing this? If I have left any information out you would like to know just ask and I'll do my best to work it out. Thanks.