Have been getting distortion on an irregular basis while recording in vocal and electric guitar etc.Also ableton has been freezing up.only recently got a mac pro and am using m-audio profire 2626 sound card.Have used the profire with my macbook pro for recording live gigs with no problems.could it be ableton software,can anybody help thanks.

intermittent problems with glitches in audio are the devil to diagnose. you've had luck with the interface and your macbook, but your new desktop system is buggy with it somehow, right?
you're asking if it's likely Abelton Live that's the problem. i'd say probably not. the most likely culprit is the m-audio interface. how's audio working in native mode on the desktop system?
update drivers? update all software? these type of fixes. there may be an AU component present in on system that's weird... ? etc... i've owned and used several M-Audio interfaces (though not yours) and never been very impressed.
good luck with this one, it's a challenge.

One handy bit of advice when I had those kind of problems is that the Hard Drive on which you are recording to needs to have a LOT of room to record audio. When it starts to fill up, it has a hard time finding sectors to write to and tosses incoming data all over the drive (and this is in real time) hence the irritating pops and glitches. One answer is using an external Firewire or even USB HD. If you are already using an external then make sure there is at least 20 to 25% available space free on it. Also before recording or using Live in any way go ahead and use the "repair disc permissions" function on your OS drive which works more or less like defragging on a PC. Hopefully this helps.

www.reverbnation.com/mortalengines

Is the issue new or it started on day one ?

One thing to try is to record from a new account, if the problem disappears, it's software based and in the original account.