pausing

[Skett]

Hi, I have recently put together a new computer. It is an
athlon xp 2500+ with 512mb ddr memory, a geforcefx 5200, a
maxtor 120gb hdd,cd burner and dvd drive. The problem is
that it keeps pausing for a couple of seconds (everything
pauses). It seems to do it at random times and is a pain
when using it for work and makes playing some games
unplayable. Thanks.
Skett.