OK, Slush's is still having issues with DDos ( and aftermath of said same ) and I am using GUIMiner to do CPU mining ( don't go there, look at my other posts first if ya gotta )

1) restart PC
2) copy the tabs you are using for the Stratum and set to slush's pool in the drop down from either solo or other ( if that is how you were mining )
3) copy your miner to a similarly named directory and make a ' new cpu miner ' ( no, not actually going to use one, i personaly use 2 and this sometimes helps )
4) find all the settings you need to pass to your miner in the command line ( NOTEPAD is your friend at this point ) and put the full directoy,miner name and those settings in at the top for where you would use a CPU miner and uncheck one of the CPU afinity boxes.
If you got quad, you will need to do this 2 more times and 2 more directories so you end up with one miner per CPU affinity
5) SAVE SETTINGS
6) run them and use the summary tab ( use the X at the top right to kill the tabs you do not need/want IF separating the CPU affinity did not help )
Look at the bottom right, if it's over 1.1Mhash/sec you are doing better than me. 

Eventualy you will find the correct core per mining directory to max out your hashes ( total hashes not per pool hashes ).  I do recomend stress testing your system with a CPU miner in it's own work tab AND having GPU miners.  There are a ton of process ticks between the sends/recieves from CUDA mining that may get you a bump of a few hundred khash/sec and it all adds up.

If this helps, I do take donations