GTP4 distorted playback making program completely unusable

I've used GPT4 for maybe a year off and on, and for the most part without any problems. Every now and then when playing back / recording (with another track playing back), I would get a weird distorted sound out of the blue. Then after stopping and restarting the playback a few times it would go away, without me adjusting any of the program settings. Occasionally it would not go away unless I restarted the program. And then again, without changing any of the program settings, it would go away. I never had a clue what was causing it, I assumed a weird fluke glitch, and since the program recorded fine 95% of the time I figured it wasn't worth worrying about. Well, now I get the distorted sound 100%. The program is completely unusable now. I get it with any track that is playing back. I even opened some of my old projects, which were done being recorded and had zero problems, and now they are all distorted too. Playback is now completely broken. I haven't fiddled with any of the program settings since I made my last problem free recordings. I checked everything in the audio settings to make sure everything is where it should be, and it was.  I came here to ask for help and noticed there was a patch released that I hadn't got, and it said some audio problems associated with windows 7 were fixed. I thought that maybe it would solve my problem, but it did not change anything. I will post a link if you want to hear what the distortion sounds like. Also what is strange is if I export the project into wav format, there is no distortion, it sounds fine. One other odd thing I noticed is the playback line that moves with the recording moves slow and stutters when it first starts.
 
I tried to post a soundcloud link to actual recordings of the distorted sound but this forum doesn't allow links apparently. But if you go to my soundcloud page  (/zenguitar-1) you can easily find the example of distortion. I also uploaded what the same track sounds like when I exported it as a wav file (it sounds perfect).
 
 
 

Thanks for the response Steve, I did notice that GPT4 was set to 44,100 and my sound card was at 48,000. But apparently, it's always been like that, and never caused a problem. I messed with those settings for a while to no effect, when lo and behold I had a genius idea: I hit the reset to default config button in my audio settings, and discovered the problem was actually the mixing latency. Apparently I had moved it from 300 ms to 10 ms, and that was the cause the problem all along. All my old projects play normally now.
 
But strangely, a new bug has cropped up, I can't start new projects anymore. Well I can, but the window that shows the instruments and tracks has disappeared. It seems to have been caused by the patch I installed yesterday. I am going to create a new thread for it, if you could take the time to read it and see if you know the answer, I'd appreciate it thanks.