I went and got the platinum chip by killing ceaser, then went and gave it to mr house, then killed mr house, and the platinum chip is not in my inventory. I want to upload yes man, but can't because I can't find the chip. Any ideas? I'm lv.29, with 70+ hrs and really don't want to restart.

You gave the chip to Mr. House there's your problem right there. You can't get the chip back once you hand it over to Mr. House.

I thought he was supposed to give it back for the underground bunker quest.

I can still side with the NCR, so not all is lost. Maybe in the second playthrough I can go the independent route.