Steam gaming platform

Hello,

Would anyone have any idea why the Steam software simply stops updating at 48%-50%? No matter what fix I've attempted (i.e. firewall/av, registry, .blob, reinstall, etc) ... nothing works, and as yet, Valve (aka Wankers Inc) barely provide any support. A week has passed and no return email.

It seems that it's a somewhat rare problem being stuck at 48-50 but no so rare in regards to generally being stuck at the update. It also seems to be limited to the actual platform update.

I did nothing to my PC. In fact, I was away for the w/end, returned to play ETW and this problem occurred out of nowhere.

//WinXP fully updated (running smooth as)
//Norton 360 (with relevant exceptions)