microsoft feed sync error

hi all,
i am using windows xp proffessional genuine
hdd-160gb, ram- 512mb, processor- intel pentium d 2mb cache, motherboard- asus ps5v.
for some time i was having this problem and my computer would get hanged and my cpu usage would be 100%. i repaired my xp from the cd since thn i have been getting this error pop0-up :- microsoft feed synchronisation has encountered a problem and needs to close.
pls. help