Running really slow

[pioneer22]

I have a late 2008 model unibody mbp, and yesterday at a gig i noticed a slight audio drop out then my audio interface crashed traktor.

I unplugged it and the computer froze so i restarted it and from that point it was running so incredibly slow really taking a long time to log in and load anything. Eventully not letting me log into that account but lets me use other accounts ive made fine.

I did put in my old hard drive and it worked fine, so i put the current hd back in and did an archive install. And im still getting really really slow performace i cant open system preferences or anything it will open after a while but then i get that wheel etc.

What I want to do is several things

1. Perform clean my mac on the user even tho im logged in in another incase its anything in the cache (how do I do this?)
2. Find out exactly whats caused it I cant take the risk of it happening again when im at a gig
3. This happened about a year ago so it cant be the new hard drive it must be some software could it be SMC fan control?

I really hope I can get this sorted

P.S Ive repaired permissions also.

EDIT how do I do a virus scan on another account?

 

[ECUpirate44]

Looks like you've exhausted all of your options as far as diagnosing the problem goes. I'd just take it to Apple.

 

[GGJstudios]

EDIT how do I do a virus scan on another account?

There has never been a virus in the wild that runs on Mac OS X. The handful of trojans that exist can be easily avoided with some education and common sense and care in what software you install:

Mac Virus/Malware Info​