not responding problems on win 7

I recently bought a hp notebook with win 7, 4 GB Ram, 600 GB HDD and plenty of cache and everything was fine. It ran well and there was no problems in the speed aspect. i booted it up today and opened a game, i hit the key board ( ctrl alt del) to be specific and them my app was not responding. i thought of it as a one off but it happended again when i re-opened the game and pressed a key (mouse was fine though). i tried microsoft word (2007); same thing, itunes; same thing then notepad and it was fine. i tried exell next and it didnt respond again.

i had my resource monitor open to see if it was pure lag but there was heeps of room in ram, cache was still had some room and hdd had 500 gig of space. my cpu was about 24-25% and reasonably steady.

this is a sudden occurence and i didnt download any new software or anything prior to the problem. please shed some light on my issue. any help will be appreciated. thanks xD

good news; (for me anyway)
i simply did what i should have ages ago and restarted the computer. perhaps as win 7 was a rush job by microsoft to amend vista my os got a little confused.