computer slow down

my computer is slow at times something is taking all the performance to 100% its not a malawaere orvirus as i have scanned pc with superanti spyware and its is protected with kaspersky antivirus.
computer running on windows wx service pack 3
512 mb ram
pentium 4 celeron

how can i post more items?
any help would be appriciated thanks
jazz

 

files attached

 

It will only make things better to upgrade to 1GB ... but as DomLuc said do the basic computer maintanence, but even though it is spyware free, it doesn't hurt to run READ & RUN ME FIRST as well. Also, it is beneficial, whether you have a Core I7 or an Intel Pentium II to do a fresh, clean install whenever you notice a significant decrease in speed or a sluggishness in you PCs respons time.

I am currently halfway through completing one for myself (although mine is because of a system upgade) I make it easier on myself by having an external HDD on which are all documents, photos, music, videos, downloads etc etc. That way when it does come to formatting and realoding, I have all of my program downloads on the External Drive as well as all of my personal data, keeping my downloads to a minumum and decreaseing set-up and personalization time from 2-3 days to 1 day. So, in other words, have all personal data on a separate HDD from your main one. It makes everything alot easier.