Something happened to the PC after knocking out traffic.

All kind time of day. As written in the topic title, a fuse blew, then there was some weird sound, type zazhevyvaya, and when he appears, load the percent approximately ~20% of process Interrupts (Hardware Interrupts and DPCs). Everything begins to lag (very much slower), but in games or really drops the fps, or just gets the picture. This sound lasts about 1-2 seconds, occurs randomly, disappears when everything becomes normal as it was. During the games, maybe every few minutes, and then about an hour never to appear. At the time of surfing and watching video (downloaded) a lot more often, sometimes every 20 seconds for 2 minutes, and again all becomes normal at a few tens of minutes.
Windows 7 x64
Mother Asrock A55M-HVS
Percents - AMD A6-3650 (base 2.6 Hz, acceleration to 3.1 Hz)
Vidyuhi - GTX 550 Ti (overclocking not more than ~+5-8%)
Hard 2 - both ancient and incomprehensible as living, but properly working without any problem with them
Operative - recently (couple months ago) bought HyperX Black 2 laths on 4 GB (chased memtest, all right)
BP - old man somewhere in the ~5+ years ago, Corsair VS550 (550 watt, respectively)