Steam games freezing after hardware upgrade, PLEASE HELP!

[TheGamezKid]

So I recently upgraded my rig, I put a i5 4690k and an asus z97-a in it with my 7950. At first there were no problems but then one day... All my steam games started freezing on me. It started with garrys mod, then cs go and now I can't play anything but terraria oddly. I know that there's a steam issue because non-steam games like battlefield 4 and farcry 3 (origin and uplay) both work, so whats the issue guys? I've tried re-installing steam and games alike and neither work. Please help, I want my games back.

Edit: Just want to point out that not all the freezes are the same, some freeze at title screen, some freeze at main menu and some let me play for a few minutes, it varies but freezes none the less.

 

[Eduello]

When you change the motherboard, you need to perform a clean installation of Windows. If you don't, these issues are almost guaranteed to happen.

 

[TheGamezKid]

When you change the motherboard, you need to perform a clean installation of Windows. If you don't, these issues are almost guaranteed to happen.

That was going to be my next try at it. Thank you, do I need to back up my files before this or will they be safe

 

[Eduello]

You need to back up all the files that are on the partition that has Windows in it; Re-installing Windows onto a partition will wipe it.

 

[TheGamezKid]

You need to back up all the files that are on the partition that has Windows in it; Re-installing Windows onto a partition will wipe it.

I'm sorry, by partition do you mean hard drive? If not could you please explain what a patition is.

 

[Eduello]

Partition is a part of the hard drive: http://en.wikipedia.org/wiki/Disk_partitioning
Basically it means that if you have Windows installed on your C drive, you need to back up all the files that you have stored on the C drive.