Problem details:i have been trying to get back to OSU, so i tried downloading the game but it has taken a while and is still not done downloading yet or does it just take a long time to download?
Consider downloading from a mirror if you are still encountering the issue; there should be a link for it below, 'Download for Windows' box. The stable client is only 4.3 MB from what I can see, so it is supposed to take not long. For the lazer client, you can download it directly from the official github page. Scroll and you'll find the Latest Release section, with 'Windows 10+ (x64)' highlighted. Click on it to download.
I'm not providing any direct download links since downloading from arbitrary links isn't a good idea.