So Steam doesn't want to install shit...

[Brotherhood Of Nod]

The title says all. Anyone know how to fix this?

After installing but failing at Homefront, I decided to stop it after like 2 hours (last time I installed it for the first time, it took 2 minutes and it actually had progress done). With that, I wanted to install Supreme Commander 2, but there was no progress done in 2 hours (same deal with the first timer, both had a CD with it). So after this crap went on, I wanted to install Portal, but the same shit happened.

Anyone got a solution to this? I restarted Steam & my computer but nothing worked.