Last September I bought a new desktop running Win7 64 bit and at the same time changed ISP to get cable fibre optic. Straightaway download speed was 60+mbps. I checked frequently on Speedtest.net until ealy November. Always 60+. Then installed a Radeon Graphics card instead of the onboard Intel graphics. I did not check on Speedtest after install. Mistake. In January it was obvious that connection speeds were really slow. My old Dell laptop running Ubuntu Linux was still getting 60+ so I knew it wasn't the ISP's problem. I disabled many start up processes to no avail. Speed was anything between 1 and 3mbps. Often the upload speed was better than the download.
Two weeks ago I finally got round to removing the graphics card. Instant success, 60+ again. Then I tried to get my Home Group working properly again, the desktop could see the Windows laptop and netbook but not vice versa. So, re-enabled normal start up and Home Group working perfectly but back to square one. Speed back down to between 1 and 3 mbps. Rebooted in to Safe Mode and hey presto, back to 60+.
Has anyone had a similar problem and can suggest the direction I should be looking to find the culprit?
I have hesitated to post any log files until someone can suggest the best options.
Many thanks in advance.