Typically, download should be about 10x upload speed and yours is on the other computer. The upload is also where it should be on the problem unit. So it is something inhibiting your download.
If yo are sure the new driver you installed is correct, I would start by deleting all the network adapter and rebooting so they will be reinstalled.
Then run chkdsk and sfc.
1st - run TFC - download from here http://www.geekstogo.com/forum/files/file/187-tfc-temp-file-cleaner-by-oldtimer/ and run from desktop = this cleans out temp files, caches, etc. Some malware might be residing there.
2nd - run CHKDSK = open a CMD prompt and type CHKDSK C: /f = scans your HDD for errors. A major cause of slowness.
When you run this, it will ask if you want to run it after a reboot. Answer yes and reboot. If you have other partitions/drives do the same for them (change drive letter). They won’t require a reboot.
If you just want to see if there is trouble on C: do not enter /f and it will run without a reboot and tell you if there were any errors. You then need to run the /f to Fix the errors.
3nd - run SFC = in the same command prompt type SFC /SCANNOW = this will fix any system file errors
If it comes back saying it found errors and could not fix them, then you will need to run DISM
You must be online for this to run
DISM.exe /Online /Cleanup-image /Restorehealth
All of these will take a long time, especially CHKDSK if it finds errors. Just wait for it. I have had it take all night to finish.