I just finished building a pc for the first time and it works perfectly except for the fact that I can not access store.steampowered.com and I'm not sure why. I'm using a TP-Link TL-WDN4800 wireless card with an Asus P8Z77-V LK motherboard. I can connect to any website I have tried so far without any problems except for steam. My little brother was able to access steam on his computer without any problems.
Steam has been coming and going all day long for me as well. It's probably due to the massive sale that is going on today since its the last day of it. This happened back when the summer sale was going on as well. Just wait it out and it will be back up and running in a few days.
why are you using wireless for gaming???? Ethernet is wwwwwwwwwaaaaaaaaaaaaaayyyyyyyyyyyyyyyy faster and more reliable.
plus its like $40 for a Cat-7 100'.Distance under 328' will not show lag or increase your ping noticeably. (Cat-7 means that you can access over 10Gbs)