this is the message in the system log (the log is currently at 24Mb! repeating the same message every a few minutes):

Aug 4 16:57:39 localhost ntpd[2201]: synchronized to 66.187.224.4, stratum=1
Aug 4 16:57:39 localhost ntpd[2201]: kernel time sync disabled 0041
Aug 4 16:59:41 localhost kernel: APIC error on CPU1: 60(60)
Aug 4 16:59:41 localhost kernel: irq 169: nobody cared! (screaming interrupt?)
Aug 4 16:59:41 localhost kernel: [<0210857a>] __report_bad_irq+0x2b/0x67
Aug 4 16:59:41 localhost kernel: [<02108612>] note_interrupt+0x43/0x66
Aug 4 16:59:41 localhost kernel: [<02108864>] do_IRQ+0x134/0x19a
Aug 4 16:59:41 localhost kernel: [<02105018>] default_idle+0x0/0x2c
Aug 4 16:59:41 localhost kernel: [<02105041>] default_idle+0x29/0x2c
Aug 4 16:59:41 localhost kernel: [<0210509d>] cpu_idle+0x26/0x3b
Aug 4 16:59:41 localhost kernel: [<02120e8b>] call_console_drivers+0xbe/0xe3
Aug 4 16:59:41 localhost kernel:
Aug 4 16:59:41 localhost kernel: handlers:
Aug 4 16:59:41 localhost kernel: [<02211c1e>] (ide_intr+0x0/0x128)
Aug 4 16:59:41 localhost kernel: [<02231ff1>] (usb_hcd_irq+0x0/0x4b)
Aug 4 16:59:41 localhost kernel: Disabling IRQ #169


anyone what do u thing is causing it, this is slowing down my computer so much.

Try disabling APIC i.e add noapic to the kernel boot options in grub.conf. You also might try turning off ntpd too

ok, can u be more specific? where exactly in that file do i add that (ie which exact line do i add it and what do i type exactly?)