Flash suddenly extremely slow, especially with code

hello

i have had cs4 for a long time now, and yesterday it suddenly took flash 10 minutes to open a document. i have loaded different documents to see what is the problem and found out it was the documents containing a lot of code (on frame1) that made him almost freeze.
it takes ages to open medium size .as files, and even editing normal stage objects takes about 5 times longer.
flash takes about 25% of cpu.
i reinstalled, restarted, cleared aso, nothing.
any ideas?