Help With Updating Minecraft

[FutileResistance]

Hey guys, I've noticed that ever since I made my own computer, minecrafts been a bit buggy. I managed to force update to 1.3.1 when it first came out but only after many re-downloads of minecraft and jars. Now that there's been a new update everything's been messed up again and I have no idea whats wrong. Basically If I try to update, it will download shortly, then cut out. The closest I've gotten was 85% but even then it stopped updating. If anyone could post possible fixes or permanent fixes I'd be grateful.


PS. Ive tried deleting .minecraft and some of the normal simple things to no avail.