Conjuration skill problems...why?

[Gobatcha]

My dark elf is a spell casting, arrow shooting, blade wielding adventurer type. I'm level 10 and I enjoy lobbing Curjurations whenever I can. I want to use some of the better spells (summon headless zombie), but it requires Conjuration skill of 50. My skill is above 50, but it's not naturally that way (using some gear to give me a boost). Why can't I use the spell? What's the point in boosting gear if I don't get the benefit? Or am I experiencing a glitch?

[Invincible121]

Are you sure you have enough magicka to cast?

[Fljotsdale]

Invincible121 is correct. The amount of Magica available to your character limits the spells s/he can cast. It you hold your cursor over the spell on your spell inventory, you will probably find it says Not Enough Magica.
A spellcaster with relatively low Magica can only use Magic as back-up to Melee or Ranged fighting, not as a primary battle tactic, usually.

You can build up Magica by increasing Intelligence - I think Conjuration is Intelligence-based, as are Alchemy & Mysticism. Willpower determines how quickly you regenerate Magica, so it is good to build up skills requiring willpower, too.

[Phreddie]

Boosting up skills does not give you the bonus of being at a higher proficiency with that skill. Say I have a conjuration skill of 30, but through various enchantments and spells I raise it to 50, or journeyman level, I cannot cast journeyman level spells. However, the spells under that school that I do cast cost less, just as they would at that level.

Another example: Acrobatics, I enchant my skill to a level past that of the level where I am allowed to dodge. At that level it also fatigues me less to jump. With the enchantments I am still fatigued less, I jump higher, and have more control over my jumps, but I do not get the skill bonus of being a journeyman/expert.