ok so I can se I could nt get much help out of this..
I have another question. what kind of headphones u suggest? When I record I can heard the instrumental from the headphone recorded in to the mic.

I know nothing about computers, but I can tell you that you want isolation headphones. I'd recommend spending at least $100, but as long as the headphones aren't really cheap (Behringer, etc...) you should be alright. It's just a matter of how accurate you want the frequency response to be.

HD280s are good but sometimes feel a little short of bass and hurt after a few hours of wearing them.

Should be able to get some for around $100.
Way cheaper than monitors + acoustic treatment but not quite as good.

I was thinking of something like http://www.thomann.de/gb/akg_k271_mkii.htm or http://www.thomann.de/gb/extreme_isolation_ex29.htm or http://www.thomann.de/gb/sony_mdr7506_kopfhoerer.htm. when u plan to spend some money u have to ask a couple of questtion here and there just to be shure.

From your link.
"Extreme Isolation EX-29 stereo headphone with extreme isolation to 29dB"

29db isn't extreme.

I think it means "reduces overall noise levels by..."

But I haven't been batting on all cylinders these past few days. Seems that I only stop to answer something I think I read right only to find out, I didn't know what the heck I was saying and to WHAT question I was saying it to.

I happen to own all of those headphones (sort of - different AKG model).

I give the EI29s to drummer, and whoever is singing (to keep the cans out of the vocal mic). I give the HD280s to the bassist (see below), and the Sony MDRs to whoever is left needing cans at that point.
If the cue mix isn't too loud, I'll loan the AKGs (k240) to the singer, and often use them for overdubs (again, if the headphone mix isn't blasting out). The frequency response of the EIs isn't great, but it's enough for the musician cutting the track.

My AKGs aren't isolation, but for monitoring, do much better than the others, imo. They're my go-to for making sure I'm hearing things right, and listening outside of the studio. Looks like the k271 model is more isolating than my k240s. They MIGHT be what you want.

I don't know a lot a bout test specs (and am not concerned w/ marketing adjectives like "extreme"), but the EIs do a better job than any other headphones I have (HD280s included - curiously, I found these to have a little bit of hyped bass response?) at keeping outside sounds, outside.

In summary:
AKGs = "truth-tellers", EIs = isolation, HD280s (good, but slightly "hyped" response), MDRs = okay (use them the least, so don't have enough quality experience to rate them)

If you have the chance, try them all for yourself, and pick the one you like best (try listening to a commercial CD you're very familiar with on each).

Finally - computer.
Just make sure it has the basic specs you need. There are a host of threads on here that address that. Just use the search button and enter "computer specs". You cover that, you're fine w/ any machine.
To be safe, you'll want 1G RAM, maybe more. A good processor (anything relatively new will do the job). and plenty of HD space. Wav files take up a lot of space - consider getting an external HD for your audio files, and dedicating the computer to software only.

http://

I love Peltor gear. European made parts + Mexican assembly = cheap goodness.

defective iMacs

i am a mac fan and longtime user, but am sad about apple's NONresponse to a widespread imac (and MB, MBP!) defect (first appearing in 2007!!!):

http://www.macnn.com/articles/07/11/30/imac.screen.failure/

while a great computer for audio recording and even editing HDV video, i would exercise caution buying one until this is resolved.
there is an online petition with over 2000 signatures (and growing)

http://www.petitiononline.com/mod_perl/signed.cgi?maclines

and even a lawsuit against apple.

http://cultofmac.com/class-action-lawsuit-over-imac-display-problems/6562

the problem appears 1-2 years of use (even light use), basically just AFTER the warranty expires, and it seems replacing the screens does not help, sooo...

2000 signatures since two years ago?

This isn't a lawsuit. More like a leisure suit :)

ha ha.
i think the petition is recent and the problem also started 'en mass' more recently. Apple was aware with these problems with powerbooks in 2007 and some iMacs.
but even 2000 $1600 computers is 3.2 million dollars, and people signing are with a school or business that have many iMacs failing.
and it isn't so leisurely if it is your computer...

Vic Firth isolation headphones here. Sound quality is sub par to all the others mentioned, but they really isolate well in both directions. For a drummer that means you don't have to crank the click as much.