Alright, finally solved it! It was a web filtering program that someone had installed earlier.
Apparently it was blocking the CSS files from downloading. For some reason though, it was still working even though I had disabled all the startup items and 3rd party services. Of course, this also explains the weird 127.0.0.1 loopback errors as well, since the filter was redirecting all traffic through itself in order to do the filtering.
K9 Web Protection
K9 Web Protection - Free Internet Filtering and Parental Controls Software

The thing that finally tipped me off to it was I started in safe mode with networking and when I opened up IE, it gave a custom error page that said the K9 filter wasn't working properly. So I'm not sure how it works but it works without changing any of the usual network settings. I had to completely uninstall it before it would let me do anything.

takze toto sa zda riesenie, ked som to precitala cele (aspon myslim)... pretoze ako on pise - mojej spolubyvajucej, co pouziva ten isty router to ide, kdzeto mne to nejde nikde inde (asi v dalsich 5bytoch s dalsimi inymi routrami a v internet cafe)..

inak - ak vypnem modem a znovu ho zapnem, bude to fungovat ako predtym,ze..? (hlupucka otazka, ale nezijem tu sama a ak to pokaslem, budem v nemilosti :)

ale to hore sa zda ako riesenie - neviem ale ako zistim kde a ci mam web filtering, ktory by mi to blokoval?
(sa ospravedlnujem ze sa mi vseetko musi vysvetlovat ako pomalsiemu stvoreniu, len tieto veci pre mna.. :/ )