i ve been noticing that my system after a while goes to "system idle"(alt+ctrl+del and u see "system idle process" on the bottom) and this usually takes up a lot of cpu -practically all of it and often crashes the whole system..this has happened to me often when working on various programs at the same time ( like listening to music while dl something and burning a cd)..or when i have music playing for a lot of time and then just try to work on something else.... ive looked up whats the purpose of the "system idle process" and came out that its supposed to be a way not to let the processor cool down(??? am i worng on this?)....anyhow ,was wondering if theres any way not to allow the system to go "on idle" or at least when it has to go then not to make it use up all the cpu??

system idle process is a way of the system to show you hoe much FREE cpu resources you have. it can't crash anything

The system idle process...to put it simply the figures in that column you are looking at, CPU time, represents the time being allocated to a process and are expressed in parts per 100, where 100 represents full CPU utilisation. A process is assigned a portion of total CPU time in order according to its interrupt level which represents that process' priority [the interrupt level is continually adjusted so that all requests are handled in a timely manner, the portion of time allotted may also be adjusted according to demand]. It stands to reason that if your CPU is not much occupied dealing with the tasks at hand then to make that sum equal 100 the unused CPU processing potential must equate to the balance - that is the system idle process' share of CPU time.
If your system idle process share is say 97, then not much processing is being done. It is not a real process.
If your system is crashing when sys idle is high, it is cos something else [everything else] stopped working..... some process is waiting for input.
In spite of the descriptions like multi-tasking a processor can only do one thing at a time ie, handle one thread at a time; it switches between threads according to the priority handed to them by the scheduler. A thread deemed urgent is given a high priority. The processor handles the thread which has the highest priority, the more time it devotes to a thread in one handling instance the more that thread's priority level is reduced until it happens that that thread is bumped by another that now has the highest priority... in this way the processor works its way down to lower priority threads, with the scheduler ensuring that priorities are adjusted so that all active threads receive some CPU time. The system idle process has zero priority - when nothing else is demanding time then the sys idle process is given a share of the CPU time. It will continue to be given shares until a thread with priority interrupts. In other words, when the sys idle process has a share of CPU time, nothing is happening.

Okay. Dima put it simply, I didn't. It was going to be simple....

hm i see that makes sense...so the system idle doesnt really belong in the process column....
what is though quite weird is that some times even though i have only 1 application running and the idle is up to 90 of the cpu (which should according to your explanation mean almost full cpu availability) the system runs extremely slolwly ....this often happens when i have jetaudio playing music for a long time for example....can only one application "exhaust" so much the processor that it doesnt work properly any longer?

Gerbil, I like being laconical :) part of the sysadmin image ;)

stan, try to clear out your temp dirs, ger a ram optimizer (though I've never seen those do any good, but who knows?), check whether the cooling on your cpu is adequate, scan for viruses, make sure you have at least 2-3 gigs free on your C drive

Dima provides sound advice.

Your CPU can be, say 90% idle, but if your system is running slowly for any reason, then your idle time will show high since the CPU can't be served with things to do at an optimum rate.

What you're telling us is that your work runs slowly (when you have work to put the CPU's way). The classic causes, in no particular order, are:

Insufficient RAM and so there is paging to hold you up. Install more RAM (say not less than 1GB; 2GB makes an enormous difference).

You have some malware or spyware running that scans your temporary files or which respawns itself. See the Spyware section of this forum and purge the gremlins.

Your hard disk is fragmented and disk transfers therefore take longer than optimal. Defrag your hard disk.

The CPU has auto-reverted to a slower speed; it does this if it overheats. Deal with that by means of fans.

For what my opinion is worth, my bet's on malware/spyware.

Let us know.

well my system is pretty old and it is a laptop pc as well...ram is pretty low (512)..another 512 would cost 1/4 -1/5 of the price of a new pc actually so i have my doubts about it...i was told that i have to get a sony one (as i have a vaio) or there might be problems and it costs over 100 euros...
the cooling system on a laptop is another story...i did then also defragmented a couple of months ago...on the c drive i have around 9 gb free and on the d around 3 ...and spyware-malware well avg didnt show much and adaware minor threats..so i suppose its the ram problem...
thanx anyway