Problem with PT10

[Lpendes]

Hey guys!
New guy here, first time user of Pro Tools. I've been using Cubase and Adobe Audition but since im attending a music school for sound engineering next year I needed Pro Tools.. anyway!

I have a PC running 32bit Windows 7 (Yes I know.. I should be using a mac.. but I just dont have the money now for one)
4GB Ram
3ghz processor
1TB HDD
The audio interface is a Yamaha Audiogram 3.

So I installed PT10 (I bought the student version because I was eligible, payed $328 for it instead of the $740 it retails here in Australia).

Struggled with iLok for about 5 hours but got it working in the end.

So PT is working fine until I tried to record. First I had the latency problem which I read all I had to do was mute the channel Im recording on and unmute it when I was done. Well when I recording in real time it sounded fine, in time, great! But when I played it back it was off. wayy off.
And now.. It doesn't even record properly anymore.. It will record about 1 bar and then cut out, I'd pause it and the click track would keep playing for about 2 counts.

It's not the computer because when I run a demo session it plays fine. I also get a message something about a buffer in the hardware.

SO.. Is it the Audio Interface? (Sorry if there is a lack of information, I'm relatively new to all these problems cos I've never had any with Cubase.)
:)

p.s.

It's driving me insane. :)