Ctrl key locks

System: Windows Vista Home Premium Service Pack 2
Model: HP Pavilion dv9700 Notebook PC
Processor: Intel Core2 Duo CPU        T5450 @ 1.66GHz
Memory (RAM): 3.00 GB
System Type: 32-bit OS

Probably not related to the above info, but it can't hurt anyone helping.

TL;DR: My computer keeps thinking that the ctrl key is pressed down when it's not. Is there a way to fix this permanently, or is my keyboard just broken? 

FULL STORY:

Today I turned on my computer, and the startup screen where it tells the computer brand and has all the Fkey and escape options for system scans took a really long time to disappear and load the Window's OS screen. I was a little perplexed and worried about it, but it didn't seem to be a problem.

Just in case, I ran a virus scan with my Avast! Free Antivirus, and it tells me that there's no problems with my computer. My unsettled feeling put at ease, I seemed okay. I opened up windows live messenger and tried to start talking to my friend, but it wouldn't let me type. Moving to Firefox because I was trying to find a solution, I found that I couldn't type there either because all these windows like save page and find would pop up.

I found out by pulling up my on-screen keyboard that my ctrl key was locked, even though I wasn't pressing it at all. I fixed it temporarily several times by either pressing the ctrl keys on the keyboard onscreen or pressing the right ctrl key several times on the physical keyboard, but only one of the two would ever work. I determined that it was left ctrl key that was causing the problem.

Now my left ctrl key has had a history of bad luck with me. First the key cap itself came off about a year ago, and then the little squishy rubber thing underneath did as well. But the button still works if I press on the space where the key used to be. I don't know if the missing key might be part of the problem, but I doubt it since it's never been a problem before.

I checked my settings, and sticky keys is not the problem. I doubt sticky keys would be able to affect the computer even outside of the OS anyways. I can't seem to find any key or setting to change to get this to stop, and the ctrl key button just randomly sticks again on the computer without warning, even when I'm not touching the laptop at all. This is really getting in the way of me even using my laptop, since I can't even type easily. Writing even this message has been very difficult, since Shift is very prone to pressing ctrl as well for some reason, though that may or may not be the fault of a lack of a key case for my Ctrl key. As I said before though, that lack of casing has never been a problem, even when I used Shift.

My computer keyboard has often switched to other languages because of this too, and I had to go into my settings and erase all my hotkeys for language changes because of this problem.

I've had to resort to using my caps lock for individual capital letters, and random save and bookmarks and find windows pop up without warning. Backspace sometimes erases whole lines because, with ctrl pressed, backspace deletes words, not letters.

If someone could give me an answer, I'd be so very thankful!