I just started playing MW and am really enjoying the deeper feel of the thing as opposed to Skyrim (though that is also pretty damn good).
Anyway, I don't have any magical items yet, nor I think, any diseases (these would show in the Actice Effects bit in the magic window right?) but my will power stat is showing as red number.
Any idea why this might be and how I can fix it. I hate having any red stats lol!

get a restore willpower potion and drink that.

In Morrowind your attributes can be drained and damaged. When they are drained they will return to normal in a short while you will have to use a restore x potion or a shrine. Unless of course it is a disease then you will have to cure it. (Though I believe that you can actually restore your attributes when diseased but you will still have other disadvantages like reduced NPC disposition.)

Best way is t take a guild guide to Ald'Ruhn and use the Imperial Cult Altar. It costs a lot (100g), but it's much easier than scouring Vvardenfell for the specific potions you need.

Oh, and FOR THE LOVE OF AZURA remove all fortification spells/enchantments before using it.

Balmora's Dummer Temple offers the same, as I recall.

Thomas a Kempe, if you've got a character with a decent Alchemy skill, do yourself a favor and create a kind of emergency potion package: a few disease cures (common, etc), several restore attribute potions, a few restore health/fatigue/magicka potions, a few fortify health potions. These are good to carry around on the road. Also, get in the habit of checking your attributes and skills after every battle to see if anything's gone red. In fact, do it after wielding a new weapon or donning armor, too. There are a few cursed items out there.

If you are magically inclined, there are spell merchants that sell restore attribute spells. I like to then create custom spells of restore mind (willpower, intelligence, personality) and restore body (strength, speed, agility, endurance).

If you buy ANY "Restore Attribute" spell from a Restoration specialist (often found at Imperial Cult Shrines or Dunmer Temples), you can go to almost any Mages Guild and get a range of weak spells made to heal each attribute, which even an unschooled barbarian should have a passable chance to succeed at casting.

As an example, a "Restore Strength" spell of 1-to-1 points for 5 seconds should consume no more than 1 point of Magicka to cast, cost about 10-20 Septims to have made, and should give you at least a 10-20% chance to cast it, even with only 5 skill in Restoration and mediocre Willpower. You could probably get by with one for Strength, one for Willpower, and one for Endurance; most of the others you can just ignore until you find a potion or healing altar. Over the course of the game, they may come in handy several times.