I was just wandering, what is the invisibility spell for?

When i used it, creatures and undead see me and keep attacking me even if i run to the other side of the room.
guards see me and saying ur trespassing here.
thus every actor/npc in the game have been equiped with see life force???
it serieously pissing me off, is this a bug??? "CANT REMEMBER HAVING THIS PROBLEM IN OBLIVION"

also having trouble with conjurate spells.
sometime's my minnions get in a fight with the npc's on my side. (quest)
Now im stuck!!!! need to go talk to a quy to compleet the quest but cant because now everytime he sees me he automaticly attacks!!!!

Oh played 4hours today and had 9 desktop crashes!! (playing vanilla skyrim patch 1.3 no mods pc version)
seriously i love beth from morrowind and oblivion but i want a functional game when i pay for it!!
Its been over a month and the game is till full with bugs what kinda lame patches are thy realy making???

(--daily bugs--)

1 texture not loading correctly
2 desktop crashes
3 killing apponents and seeing them falling trough the floor. Oh there go's my ([censored]) loot.

these were problems on release were now "1 MONTH" later 3 patches along the road and still nothing changed??? ((( Are these patches a joke??? )))

Anyone else have these problems?

cheers

Depends on your Sneak skills.
Edit:Also you need to crouch to the potion works.Also try use some sneak items that buffs your steps.
Edit 2.0: I see that you have tons of problems there bro.What's your computer perfomance?Also didn't accidentaly one of your minions/quest companions hited each other?Something siimilary happend to me...

They can still hear you, so you need to sneak (which, if they're close, means both crouching and walking.)

Huh - I have patched up to 1.3 and have honestly not had these problems at all, haven't even used tweak guides or anything.. And happily, 1.3 fixed the stutter when I run over-world, which was frustrating. I have only CTD'd 2x in 100 hours of gameplay and one time was something I specifically did, and I haven't yet seen NPCs drop through the floor. Frustrating - only once in a great while have I seen a minor texture issue, but not enough to really even distract me. I wonder if the hardware/software forums might have some info for you - some people have been using various tweak guides that are circulating, so maybe that could help.

As for invisibility... I know it works, but not quite the same way it did in OB. It definitely works to stealth by someone that has not yet detected you, but a high level mob who was already in combat with you will still lob spells, for example, where you were standing. I was able to get away from an Adept going invisible, but he hit me at least 2 more times, though it didn't break invis, as I was trying to run the hell out of the room. I didn't interact or use a weapon, and his aggro dropped once I had back-peddled out of the area while invisible. That was my experience with it anyway.

Try the inofficial 4gb exe to fix texture problems and crashes. It did it for me.

Invisibility seems to be..nerfed in Skyrim. I guess the days of invisible stealth are over.

Kinda, like someone said. It depends on your sneak.

Cheers

Invisibility is working fine for me. They can still hear you even if you're invisible and they know where you were. So they often will walk towards where you were or cast a spell there. If they hit you randomly or walk into you randomly it alerts them.

No problems here on PC or XBOX with invisibility.

Works fine for me, remember that they can still hear you, so it's more like an enhancer to stealth rather than a "i'll go invis and run past everyone" effect.
I also dont think it works if they see you cast it.

Yeah, there's a couple things you can do to make this work better. Get footwear with the muffle attribute, from either the thieves guild or the dark brotherhood. Alternatively, learn the muffle spell and use it whenever you want to sneak. If you're invisible they'll still hear you, and detect your location (note, go into third person, you're still slightly visible, so this makes sense that someone hearing you can discern where you are). Besides that the Shrouded hood adds 25% to sneaking. If you equip both those items it pretty much won't matter what your sneak level is, and the invisibility should work perfectly as long as you were already hidden when it gets activated.

If you upgrade your sneak enough you won't even need to worry about all that, just invest in the silent running perk (forget the exact name, but you'll know it when you see it).