Microsoft Loopback Adapter Killed my router :( :( Help

Hey guys, I was trying to install Oracle 10g on my dynamic IP'd PC and had to install a Loopback adapter. I was connecting via a linksys router to a motorla cable modem. Oracle installed fine, and my pc internet connection was just fine.

However, all this happened while my roomie was away, so when he got back, we realised that only one computer could be detected by the Router at one time. What's going on?

I had to add my host name to the cwindows/system32/drivers/etc/hosts file. however i removed all the thigns i added and also did a system restore to a configuration before this stuff. I also unplugged, reset the router. yet the router is nuts and isnt allowing two or more comps.

one thing i noticed was when i ran ipconfig, the unroutable ip i assigned to the loopback adapter was appearing on my roomies comp ugggghhh

If any1 knows whats up Please help....