Large downloads become corrupted.

Hey techsupport,

A few days ago I refreshed my Alienware laptop (not full factory reset), because I was a silly goose and fell for one of those stupid teamviewer phone scams. Ever since then, I've been having issues with large downloads. I tried downloading some games I own on gog.com and each of them was apparently corrupted while running the installer. I figured that was just a problem on their end so I let it go, but the same thing is happening everytime I try to download larger games on Steam (it stops and says "Download corrupted"). After some quick google-fu and searches here it sounds like it could be a memory issue. I ran windows memory diagnostic and it didn't find anything wrong.

The laptop is relatively new (about a month old). Didn't have any issues before this. I'm running Windows 8. I also ran several malware and antivirus scans to make sure the crap off that scam was cleaned off.

Any ideas as to what I can do? Thanks alot friends, appreciate it greatly.