My games won't save on steam

Have you tried the "backup local content" option to see what that does? It sounds like a problem with the Steam install rather then with either of the two games themselves.

If you are using the F key option to save try hitting the escape key to bring up the main options to save a game level to see if that will work. Sometimes the F key quick save option is problematic even for non Steam titles.

Only Bioshock and borderlands do thing all my other games save

I would try reinstalling the Steam engine itself not the games. You've already went that route and got nowhere. That's apparently where the bug is being seen.

I have to say I'fve never run into this one having had a number of Steam titles over the years since 2004-5 with Helf Life 2. It's certainly an odd one! Even with the 3rd developer mods(HL2 based addon games - 1-10 levels) they always are able to save while several of those love to crash! Steam Client dll errors and HL2.exe stops responding are the typical errors seen.

When running a search on the problem you are seeing someone at the 2kgames site posted a possible solution to look at for Bioshock. Can not save game - full game (Steam) [Archive] - 2K Games Forums

The other thought on this would be unfortunately scrolling through the Steam forums threads for anyone else running into this one. it sounds like where the game saves are designated to go is where the problem is however according to the post found on the 2kgames.com site.

With the reinstalls you might be running into a duplicate folder type problem. If that's the case then it would see the drive as being full rather then being able to overwrite things in the first by the same name.

You woulldn't have to uninstall the games but simply uninstall the Steam item itself through the Programs + Features option in the Control Panel to separate that from any games already on. The fresh download, install, and then logging in would see all titles back in the game library without the major hassles for reistalling everything.

The best first move however would be running a search on the Steam forums since that's where most of the problems as well as many solutions would be found. I'm sure someone else has run into this as well while maybe not naming a thread there the same. http://store.steampowered.com/forums/